heart health

Are Omega-3 Supplements Safe?

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The Flaws And Blind Spots In This Study

Author: Dr. Stephen Chaney

Pendulum
Pendulum

Has the omega-3 pendulum swung again? The recent headlines are downright scary. For example:

  • “Fish Oil May Increase the Risk of Stroke and Heart Conditions.”
  • “Fish Oil Supplements May Cause Harm, Study Finds. Is It Time to Ditch Them?”
  • “Fish Oil Supplements May Lead to Heart Problems”.
  • “Regular Use of Fish Oil Supplements Might Increase, Rather Than Lessen, The Risk of First Time Heart Disease and Stroke Among Those in Good Cardiovascular Health.”

Yikes! That sounds bad. Should we be thinking about giving up our omega-3 supplements?

But wait. Just a few weeks earlier we were reading headlines about the benefits and lack of side effects from omega-3 supplements. That’s confusing. Which headlines are correct?

To answer these questions:

  • I will point out the flaws and blind spots in the study.
  • I will strip away the hyperbole and put the headlines into perspective.

How Was The Study Done?

clinical studyThe investigators made use of data from the UK Biobank Study. The UK Biobank Study is a large, long-term study in the United Kingdom which was designed to investigate the contributions of genetic predisposition and environmental exposure [including diet and supplementation] to the development of disease.

The UK Biobank Study enrolled 502,461 participants, aged 40-69 years, between January 1st, 2006 and December 31st, 2010. Participants were followed from entry into the program until March 31st 2021, an average of 11.9 years.

The current study excluded any participants who had a diagnosis of atrial fibrillation, heart failure, heart attack, stroke, or cancer at entry into the study, leaving 415,737 participants.

The participants were:

  • 55% women.
  • Average age of 56 years, with 83.4% of them below 65 years old at entry into the study.
  • 94.5% white.

The study was designed in a unique manner, in that it was designed to test the effect of omega-3 supplements on 6 specific transitions:

  • Primary prevention. This measured the transition of healthy (no diagnosed heart disease) people to either atrial fibrillation, major cardiovascular events, or death.
  • Secondary prevention. This measured the transition from atrial fibrillation to either major cardiovascular events or death.
  • Tertiary prevention. This measured the transition from major cardiovascular events to death.
  • Major cardiovascular events were further broken down to heart attacks, stroke and heart failure.

Participants were asked whether they used fish oil supplements when they entered the study and were categorized as either regular users or non-users. [Note: The users were not asked the dose or brand of fish oil supplements they used.]

Deaths were obtained from the national death registry and disease diagnosis from the National Health Service.

Are Omega-3 Supplements Safe?

omega-3 fish oil supplementHere is what the study found.

Primary Prevention – For healthy individuals (defined as having no diagnosed heart disease) using omega-3 supplements for an average of 11.9 years:

  • Increased the risk of atrial fibrillation by 13%.
  • Did not affect the risk of major cardiovascular events and death were unaffected by omega-3 supplementation.
  • When major cardiovascular events were broken down to their component parts, omega-3 supplementation:
    • Decreased the risk of heart failure by 8%.
    • Increased the risk of stroke by 5% (this was just barely statistically significance).
    • Did not affect the risk of heart attack.

Secondary Prevention – For individuals with atrial fibrillation omega-3 supplementation:

  • Decreased the risk of major cardiovascular events by 9%.
  • Decreased the risk of death by 8%.
  • When major cardiovascular events were broken down into their component parts, omega-3 supplementation:
  • Decreased the risk of heart attacks by 15%.
  • Had no effect on the risk of stroke or heart failure.

Tertiary Prevention – For people who suffered major cardiovascular events during the study omega-3 thumbs upsupplementation:

  • Decreased the risk of death by 8%.

Since this is a very complex set of data, I have coded positive results in green and negative results in red.

And as if these complexities were not enough, when the investigators broke these effects down by population groups:

  • Omega-3 supplementation decreased the transition from healthy to death for men (7% decrease) and participants older than 65 (9% decrease).

I will discuss the significance of these observations below.

The authors concluded, “Regular use of fish oil supplements might be a risk factor for atrial fibrillation and stroke among the general population but could be beneficial for [reducing] progression of cardiovascular disease from atrial fibrillation to major adverse cardiovascular events, and from atrial fibrillation to death.”

In short, they were suggesting that omega-3 supplements should be avoided by the general population because they have no positive benefits and might increase the risk of atrial fibrillation and stroke. But omega-3 supplements may be useful for those who already have heart disease.

Some of the articles you may have read about the study repeated this message. Others just emphasized the negative aspects of the study.

But is this message accurate? Let me start by discussing the flaws, blind spots, and hidden data in this study. Then I will summarize the 3 key findings of the study and tell you what they mean for you.

The Flaws, Blind Spots, And Hidden Data In This Study

flawsFlaws: As I said above, there were two major flaws in the study.

Flaw #1: The study did not identify the dose of supplement used. This is important because the increased risk of atrial fibrillation and stroke is primarily seen in clinical trials using high dose omega-3 supplements.

Flaw #2: This was an association study which cannot prove cause and effect. However, the authors of this study reported it as showing that omega-3 supplement use caused atrial fibrillation and stroke – and all the news reports on the study have repeated that claim.

Flaw #3: Other experts have pointed out that the authors inflated the risks associated with omega-3 supplementation by reporting relative risk rather than absolute risk. Let me try to simplify the distinction.

The risk of atrial fibrillation was 4.24% in the non-supplement users and 4.80% in the omega-3 supplement users. That is an absolute increase in risk of 0.56% (4.80% – 4.24%). This is the increase in risk you actually experience. In contrast, 4.80% is 13% greater than 4.24%, which is how relative risk is calculated.

In response to the questions you are probably thinking:

  • Yes, this is a perfect example of the Mark Twain quote, “There are lies. There are damn lies. And then there are statistics.”
  • Yes, all the percentages reported in this study are based on relative risk and are, therefore, inflated. However, I do not have access to their data, so I cannot tell you the absolute risk associated with their other observations.

Blind Spots: In their paper the investigators recommended against the use of omega-3 supplements to prevent heart disease because their data showed:

  • No benefit of omega-3 supplementation for preventing major cardiovascular events and deaths in a healthy population.
  • But did suggest an increased risk of atrial fibrillation and stroke in that same population.

However, their blind spot was in underestimating the difficulty of showing the benefit of any intervention in a healthy population. The example I always use is statin drugs. Statin Drugs:

  • Dramatically reduce the risk of a second heart attack and/or death in people who have already had a heart attack.
  • Reduce the risk of heart attacks in people who are at high risk of heart attacks.
  • Cannot be shown to reduce the risk of heart attacks in a healthy population.

This study suggests that omega-3 supplements are no different. In this study, omega-3 supplements:

  • Reduced the risk of death in people who had already experienced a major cardiovascular event like a heart attack or stroke.
  • Reduced the risk of major cardiovascular events and death in people with atrial fibrillation, which puts them at high risk for a heart attack or stroke.
  • Could not be shown to reduce the risk of major cardiovascular events or deaths in a healthy population.

Hidden Data: There are some important data that were buried in the text and supplemental figures but were Skepticignored in the concluding remarks of this study and all the articles written about it. For example:

  • The original study and all articles written about the study reported that omega-3 supplementation increased the risk of stroke in otherwise healthy individuals but ignored the observation that omega-3 supplementation decreased the risk of heart failure in that same group.

The second example of hidden data likely represents another blind spot of the authors. They concluded that omega-3 supplementation had no benefit for healthy individuals without asking whether omega-3 supplements might benefit higher-risk subpopulations within this group. To help you understand this statement let me start by giving you some perspective.

As I said above, statin drugs cannot be shown to reduce the risk of heart attacks in a healthy population. But when you include people at high risk of heart disease with healthy people in the dataset, you start to see a reduced risk of heart attacks.

Similarly, with supplements you often see no benefits with the general population, which is what is usually reported in the media. But when you look at higher risk groups within that population, the benefits of supplementation emerge.

This study is no different:

  • For healthy individuals, omega-3 supplementation had no effect on deaths during the 12-year follow-up period.
  • However, omega-3 supplementation reduced the risk of death by 9% for both men and people ≥ 65. These represent two groups with elevated risk of heart disease within the otherwise healthy population.
  • Once again, these data were completely ignored.

What Does This Study Mean For You?

This study made 3 major points:

Point #1: Let me start with the one you’ve heard the most about. The risk of atrial fibrillation and stroke associated with omega-3 supplementation is real. We should not ignore it.

But what this study and most of the reports on the study didn’t tell you is that the risk is dose dependent. The risk is primarily seen with high doses of omega-3s. While no one has done a comprehensive dose response analysis, I can tell you that these side effects are:

  • Seldom reported in clinical studies at doses of 1 gm/day or less.
  • Sometimes reported in clinical studies at doses of ≥2 gm/day.
  • Frequently reported in clinical studies at doses of ≥4 gm/day.

However, atrial fibrillation and stroke occur in a very small percentage of omega-3 users, even at 4 gm/day. At this point we have no idea why some people are susceptible to these side effects and others are not. More research in this area is clearly needed.

Until we know more about who is at risk, my recommendation for people who are trying to reduce the risk of heart disease is to rely on something called the Omega-3 Index to determine your individual omega-3 needs rather than using high-dose omega-3 supplements.

  • The Omega-3 Index measures the amount of omega-3 fatty acids in your tissues. It is determined by the amount of omega-3s you consume and how you metabolize them, so it is individualized to you.
  • An Omega-3 Index of 4% is associated with a high risk of heart disease, while an Omega-3 Index of 8% is associated with a low risk of heart disease. There is no evidence that more than 8% provides additional benefit.
  • Most importantly, it only takes 1-1.6 gm/day of omega-3s to raise your Omega-3 Index from 4% to 8%. At these doses your risk of atrial fibrillation and stroke is extremely small.

For example, a recent meta-analysis of 29 studies with a total of 183,292 participants reported that people with an 8% Omega-3 Index had:

  • Decreased risk of ischemic stroke (stroke due to blood clots) with no detectable increased risk of hemorrhagic stroke (stroke due to bleeding), and…
  • No detectable increased risk of atrial fibrillation.

I recommend getting your Omega-3 Index determined, and if it is low, increasing your omega-3 intake to get it into the 8% range. Some people go from 4% to 8% more rapidly than others, so you may need to repeat the test several times to optimize your Omega-3 Index.

If your health professional doesn’t have access to the Omega-3 Index test, you can order it from https://omegaquant.com (I have no financial stake in this company, but I know it as a reputable source of the Omega-3 Index test).

Does The Professor Plan To Reduce His Intake Of Omega-3 Fatty Acids? Three weeks ago, I shared thatprofessor owl my wife and I have been taking around 3 gm/day of omega-3 supplements for the past 40 years. Now that the association of atrial fibrillation and stroke with high dose omega-3 intake has been firmly established, some of you may be wondering whether we plan to decrease our intake of omega-3 supplements.

The answer is, “No”. Remember that the increased risk of atrial fibrillation and stroke is only seen for a small subset of people taking high-dose omega-3 supplements. If we were part of that subset, we would likely have experienced one of those side effects by now.

However, if you are considering omega-3 supplementation for the first time, you don’t know whether you are part of that subset or not. So, my advice remains the same. Rely on optimizing your Omega-3 Index rather than high-dose omega-3 supplementation.

Point #2: Healthy individuals (those with no symptoms of heart disease) do not benefit from omega-3 supplementation. As I pointed out above, this ignores data from their study, namely.

  • Omega-3 supplementation reduced the risk of heart failure in healthy subjects.
  • Omega-3 supplementation reduced the risk of death in higher risk groups within the healthy population (namely men and people 65 and older).

Confusion Clinical StudiesAs I discussed above, this is a pattern seen with statin drugs and most nutritional supplements. Simply put, you can’t show any benefit of statin drugs or most nutritional supplements in a “healthy” population, but you can show benefit when you focus on higher risk individuals within the “healthy” population.

The problem, of course, is that most of us don’t really know whether we are “healthy” or not. For millions of Americans the first indication that they are at risk from heart disease is sudden death from a heart attack or stroke.

With that in mind, I will leave the decision about whether you want to supplement with omega-3s up to you. But if you decide to supplement, I recommend you optimize your Omega-3 Index rather than using a high dose omega-3 supplement.

Point #3: People with heart disease benefit from omega-3 supplementation. This recommendation is becoming non-controversial, so I won’t comment further other than to say high dose omega-3 supplements are probably not needed unless prescribed by your health professional.

The Bottom Line

You have been asking me about recent headlines saying that omega-3 supplements may increase rather than decrease the risk of heart disease. So, I analyzed the study behind the headlines. The study makes 3 claims:

  • Omega-3 supplements increase the risk of atrial fibrillation and stroke when taken by healthy people.
  • Omega-3 supplements are of no benefit for healthy individuals.
  • Omega-3 supplements are beneficial for people who have heart disease.

In the article above I review the flaws, blind spots, and hidden data in the article and discuss what it means for you.

For more details about this study and what it means for you read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

 ______________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 _______________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Is The Mediterranean Diet Healthy For Women?

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What Does This Study Mean For You? 

Author: Dr. Stephen Chaney 

There is a well-known health disparity in clinical studies related to health. For years most of the studies have been done by men for men. Women have been assumed to experience the same benefits and risks from diet choices as men. But that hasn’t always proven to be true.

The Mediterranean diet is no exception. For example, it has garnered a reputation of reducing heart disease risk for both men and women.

However, most studies on the Mediterranean diet have included primarily male participants or did not report sex specific differences in outcomes.

And the few studies that reported sex specific outcomes have been inconsistent.

  • Some studies have found that men and women benefitted equally from the Mediterranean diet.
  • Other studies have reported that men benefitted more than women.

However, these were all small studies. No meta-analyses have been reported that focused on the heart benefits of the Mediterranean diet for women.

The study (A Pant et al., Heart; 109: 1208-1215, 2023) I will describe today was designed to fill that gap.

How Was The Study Done?

clinical studyThe investigators started by screening the literature to find studies that:

  • Measured adherence to the Mediterranean diet using the original MDS (Mediterranean Diet Score) or more recent modifications of the MDS.
  • Included women ≥18 years without previous diagnosis of clinical or subclinical heart disease.
  • Performed the study with only women participants or organized their data so that the data pertaining to women could be extracted from the study.

The investigators then performed a meta-analysis on data from 722,495 women in 16 studies published between 2006 and 2021 that met these criteria. These studies followed the women for an average of 12.5 years. The studies were primarily conducted in the United States and Europe.

The individual studies divided participants into either quintiles or quartiles and compared participants with the highest adherence to the Mediterranean diet to those with the lowest adherence.

  • The primary outcomes measured were total mortality and the incidence of CVD, cardiovascular disease (defined as including CHD (coronary heart disease), myocardial infarction (heart attack), stroke, heart failure, and cardiovascular death).
  • The secondary outcomes measured were stroke and CHD, coronary heart disease (heart disease caused by atherosclerotic plaque build up in the coronary arteries).

Is The Mediterranean Diet Healthy For Women?

Mediterranean Diet FoodsWhen comparing the highest to the lowest adherence to the Mediterranean diet:

  • The incidence of CVD (cardiovascular disease) was reduced by 24%.
  • Total mortality during the ~12.5-year follow-up was reduced by 23%.
  • The incidence of CHD (coronary heart disease) was reduced by 25%.
  • The risk of stroke was reduced by 13%, but that risk reduction was not statistically significant.
    • The risk reduction for both CVD and total mortality was similar to that previously reported for men.
    • Risk reduction for CVD was slightly higher for women of European descent (24%) than for women of non-European descent (21%). The later category included women of Asian, Native-Hawaiian, and African – American descent.

The authors concluded, “This study supports a beneficial effect of the Mediterranean diet on the primary prevention of CVD and death in women and is an important step in enabling sex-specific guidelines.”

I would add that the data from women of non-European decent suggests that genetic background and/or ethnicity may influence the effectiveness of the Mediterranean diet at reducing heart disease risk, but this effect appears to be small.

What Does This Mean For You?

The results of this study are not unexpected. But that doesn’t mean that studies with women are not valuable. There have been several examples in recent years where health or medical advice based on studies with men needed to be modified for females once the studies were repeated with women.

Before covering what this study means for you, I should point out that while women often fear breast cancer most, heart disease is their number one killer, as the graph on the left shows. In fact, a woman’s risk of dying from coronary heart disease is 6 times greater than her risk of dying from breast cancer.

This study shows that following a Mediterranean–style diet lowers their risk of developing and dying from heart disease. But the Mediterranean diet is not alone in providing these health benefits. It is simply a whole food, primarily plant-based diet that reflects the food preferences of the Mediterranean region.

The DASH diet, which reflects the food preferences of Americans, and the Nordic diet, which reflects the food preferences of the Scandinavian countries, are equally heart healthy. In fact, any whole food, primarily plant-based diet will reduce the risk of heart disease. You should choose the one that best fits your food preferences and lifestyle.

Of course, diet is just part of a holistic approach for reducing heart disease risk. Other important risk reduction strategies include:

  • Don’t smoke.
  • Exercise and maintain a healthy weight.
  • Manage stress.
  • Avoid or limit alcohol.
  • Know your numbers (cholesterol, triglycerides, and blood pressure, for example).
  • Manage other health conditions that increase the risk of heart disease (high blood pressure, diabetes, and high cholesterol, for example).

The Bottom Line

Most studies on the heart health benefits of the Mediterranean diet have been done with men or have not analyzed the data from men and women separately. A recent meta-analysis combining data from 16 studies with 722,495 women showed that the Mediterranean diet was just as heart healthy for women as it was for men.

The authors concluded, “This study supports a beneficial effect of the Mediterranean diet on the primary prevention of CVD and death in women and is an important step in enabling sex-specific guidelines.”

For more details on this study and information on other diets that are heart healthy, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

_____________________________________________________________________________My My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 _____________________________________________________________________

About The Author 

Dr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.

Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”.

Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

Since retiring from the University of North Carolina, he has been writing a weekly health blog called “Health Tips From the Professor”. He has also written two best-selling books, “Slaying the Food Myths” and “Slaying the Supplement Myths”. And most recently he has created an online lifestyle change course, “Create Your Personal Health Zone”. For more information visit https://chaneyhealth.com.

For the past 45 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Are Calcium Supplements Heart Healthy?

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Should You Follow Your Doctor’s Advice About Calcium Supplementation?

Author: Dr. Stephen Chaney

Heart ConfusionAre calcium supplements good for your heart or bad for your heart? If you don’t know the answer to that question, don’t feel badly. You have every right to be confused. Some studies say that calcium supplements increase heart disease risk while others say they decrease heart disease risk. The headlines have veered between “killer calcium” and “beneficial calcium”.

The trend appears to be moving in a positive direction. In recent years most of the studies have suggested that calcium supplements either decrease heart disease risk or have no effect on heart disease risk.

However, the medical profession has been slow to take note of this trend. Most medical societies and health professionals have focused on earlier studies and are still recommending that their patients get calcium from food rather than from supplements. I will talk more about that recommendation below.

With this context in mind, this week I will review and discuss the results from the latest study (MG Sim et al, Heart, Lung and Circulation, 32: 1230-1239, 2023) on the effect of calcium supplementation on heart disease risk.

How Was This Study Done?

Clinical StudyThe authors of this study performed a meta-analysis of 12 double-blinded randomized clinical trials with 87,899 participants comparing the effect of a calcium supplement versus a placebo on heart disease outcomes (heart attack, stroke, heart failure, cardiovascular mortality, and all-cause mortality).

The studies included in this analysis:

  • Used calcium doses from 500 mg/day to 2,000 mg/day.
  • Used supplements with calcium coming from a variety of sources (calcium carbonate, calcium citrate, calcium gluconolactate, and tricalcium phosphate).
  • Ranged from 18 months to almost 12 years in length.
  • Were performed with population groups from a wide range of countries (United States, England, France, Australia, New Zealand, European Union, Denmark, and Thailand).
  • Included calcium supplements with and without vitamin D.
  • Were primarily (86% of participants) conducted with post-menopausal women. One small study (0.3% of participants) was conducted with non-osteoporotic men. The rest were conducted with mixed populations (men and women) diagnosed with colorectal adenoma.

Are Calcium Supplements Heart Healthy?

calcium supplementsThis is the largest meta-analysis performed to date of double-blind, placebo-controlled randomized clinical trials on the effect of calcium supplementation versus a placebo on heart disease outcomes. This study found no effect of calcium supplementation on:

  • Heart attack.
  • Stroke
  • Heart failure.
  • Cardiovascular mortality.
  • All-cause mortality.

This study also evaluated potential confounding variables and found no effect of calcium supplementation on heart disease risk for:

  • Calcium supplements with and without vitamin D.
  • Dosage of calcium in the supplements (The dosage ranged from 500 mg/day to 2,000 mg/day).
  • Females (I suspect the number of males in this study was too small to come to a statistically significant conclusion).
  • Duration of calcium supplementation ≤ 5 years (The shortest duration of calcium supplementation in these studies was 18 months).
  • Different geographical regions.

However, this meta-analysis reported considerable variation between studies included in the analysis. Simply put,

  • Some studies showed an increase in heart disease risk.
  • Some studies showed a decrease in heart disease risk.
  • Some studies showed no effect on heart disease risk.

What this analysis showed was that when you combine all the studies, the aggregated data is consistent with calcium supplementation having no effect on heart disease risk.

The authors concluded, “Calcium supplementation was not associated with myocardial infraction [heart attack], stroke, heart failure, and cardiovascular/all-cause mortality. Further studies are required to examine and understand these associations.

Should You Follow Your Doctor’s Advice About Calcium Supplementation?

Doctor With PatientAs I said above, most medical societies and health professionals have focused on earlier studies and are still recommending that their patients get calcium from food rather than from supplements. That may be the advice you are getting from your doctor.

Before you assume your doctor isn’t keeping up with the latest science and ignore his or her advice, we should ask why they are giving that advice. The top three reasons most medical societies give for recommending dietary sources of calcium are:

1) Some studies do show an increased risk of heart disease associated with calcium supplementation. The prime directive for health professionals is to do no harm. Yes, the average of all studies shows no effect of calcium supplementation on heart disease risk. But what if the studies showing increased risk are true for some of their patients? Those patients could be harmed. 

Are you someone who might be at increased risk for heart disease if you take calcium supplements. The short answer is we don’t know because previous studies have not asked the right questions. 

In my opinion, it is time to pause additional studies and meta-analyses on calcium supplementation and heart health until we have gone over existing studies with a fine-tooth comb to figure out why the results differ so wildly. For example, we need to ask whether the effect of calcium supplements on heart disease risk is influenced by things like:

    • Age or ethnicity of participants.
    • Other preexisting health conditions.
    • Other lifestyle factors (exercise is probably the most important, but others may be involved as well).
    • Diet context. For example, we already know that the effect of eggs and dairy on heart health is influenced by diet context. [I have covered this for eggs in a previous issue of “Health Tips From the Professor”.]
    • Other unanticipated variables.

Only when we have identified variables that might influence the effect of calcium supplements on heart disease risk, will the scientific community be able to design studies to identify the population groups who might be adversely affected by calcium supplementation.

This would allow health professionals to make informed decisions about which of their patients should avoid calcium supplementation and which of their patients would benefit from calcium supplementation. 

2) We really don’t need the recommended RDAs for calcium to build strong bones. The Healthy Bonerecommended RDAs for calcium are 1,000 mg/day for adults 19-50, 1,000 mg/day for men and 1,200 mg/day for women 51-70, and 1,200 mg/day for both men and women over 70. But do we really need that amount of calcium to build healthy bones? 

I have discussed this topic in detail in a previous issue of “Health Tips From the Professor”. Here are the key points:

    • The current RDAs are based on calcium needs for people consuming the typical American diet and following the typical American lifestyle. If that is you, the current RDAs probably apply.
    • However, strong bones are absolutely dependent on three things, adequate calcium, adequate vitamin D, and adequate weight-bearing exercise. Most recent studies of calcium supplementation and bone density include adequate vitamin D, but almost none of them include exercise. Previous studies have been inadequate.
    • The best calcium supplements contain certain nutrients besides vitamin D that optimize bone formation. I have listed those nutrients in the article cited above.
    • Our ability to use calcium to build strong bones is dependent on diet (something I call a bone-healthy diet) and lifestyle (something I call a bone-healthy lifestyle).
    • For more information on each of these points, read the article I referenced above.

In short, I agree that the current calcium RDAs may be too high for individuals consuming a bone-healthy diet and following a bone-healthy lifestyle. But the current calcium RDAs are likely accurate for people consuming the typical American diet and following the typical American lifestyle.

    • While we do not have a calcium RDA for populations following a bone healthy diet lifestyle, some studies suggest that 700-800 mg of calcium/day may be sufficient for this group.

3) Calcium from supplements is absorbed faster and gives higher blood level spikes than calcium from foods. That could be a problem because high blood levels of calcium are associated with calcification of our arteries, which is associated with increased heart disease risk. 

This is a theoretical concern, because high blood calcium levels from supplementation are transitory, while it is continuous high blood calcium levels that are associated with calcification of our arteries.

However, it is a plausible concern because most supplement companies design their calcium supplements based on how quickly they get calcium into the bloodstream rather than how effectively the calcium is utilized for bone formation. Here are my recommendations:

    • Choose a calcium supplement that provides RDA levels of vitamin D plus other nutrients shown to support strong bone formation.
    • Choose a calcium supplement supported by clinical studies showing it is effectively utilized for bone formation.

4) We should be getting our calcium from foods rather than supplements. dairy foods

While it is always easy for doctors to recommend that we get our nutrients from food rather than supplements, they need to ask whether we are getting those nutrients from our diet. For calcium the data are particularly sobering.

    • The average American gets around 740 mg of calcium/day from their diet. That is probably enough for the small percentage of Americans following a bone healthy diet and lifestyle. But it is 260-460 mg short of the 1,000-1,200 mg/day recommended for older adults with the typical American diet and lifestyle.
      • And for the average American, around 70% of their calcium intake comes from dairy foods.

       

      • So, Americans who are following a typical American diet and lifestyle and are restricting dairy may require 800-1,000 mg/day of supplemental calcium unless they carefully plan their diets to optimize calcium intake.

       

      • Finally, vegans average about 550 mg/day from their diet. That might be borderline even if they were following a bone healthy lifestyle.
    • In short, we cannot assume our diet will provide enough calcium for strong bones unless we include dairy foods and/or plan our diet very carefully. Some degree of supplementation may be necessary.

How Much Calcium Do You Need?

Questioning Woman

I have covered a lot of territory in this article, so let me summarize the four concerns of the medical community and answer your most important question, “Should you take calcium supplements?”

1) Calcium supplements may increase the risk of heart disease for some people.

That is true, but we have no idea at present who is at increased risk and who isn’t. So, we should minimize our risk by taking the precautions I describe below.

2) We don’t need RDA levels of calcium to build strong bones. That is probably true if you are one of the few people who follows a bone healthy diet and lifestyle, but it isn’t true if you follow the typical American diet and lifestyle.

  • The current RDAs of 1,000 – 1,200 mg/day are a good guideline for how much calcium you need if you follow the typical American diet and lifestyle.
  • If you a one of the few people who follow a bone healthy diet and lifestyle (For what that involves, read this article) you may only need 700-800 mg/day. But we don’t have clinical studies that can tell us what the actual RDA for calcium should be under those circumstances.

3) Calcium from supplements is absorbed faster and gives higher blood calcium spikes than calcium from foods. You may remember that the theoretical concern is that even short-term spikes of high blood calcium may lead to calcification of your arteries, which increases your risk of heart disease. So, the important question becomes, “What can we do to minimize these spikes in blood calcium levels?”

  • We should avoid calcium supplements that brag about how quickly and efficiently the calcium is absorbed. That could lead to calcium spikes. Instead, we should look for calcium supplements that are backed by clinical studies showing they are efficiently utilized for bone formation.
  • We should look for calcium supplements that include RDA levels of vitamin D and other nutrients that optimize bone formation. You will find more information on that in the same article I referenced above.
  • Some experts recommend that calcium supplements be taken between meals. But it is probably better to take them with meals because foods will likely slow the rate at which calcium is absorbed and reduce calcium spikes in the blood.
  • We are told to limit calcium supplements to less than 500 mg at any one time because calcium absorption becomes inefficient at higher doses. It might be even better to limit calcium to 250 mg or less at a time to reduce calcium spikes in the blood.

4) We should get calcium from foods rather than supplements.

  • Many Americans do not get enough calcium from diet alone, especially if they avoid dairy foods. So, some degree of calcium supplementation may be necessary. I have given some guidelines depending on your diet and lifestyle above.
  • The amount of supplemental calcium needed is relatively small. I do not recommend exceeding the RDA unless directed to by your health professional.

The Bottom Line 

Some studies say that calcium supplements increase heart disease risk while others say they decrease heart disease risk. The headlines veer between “killer calcium” and “beneficial calcium”.

The trend appears to be moving in a positive direction. In recent years most of the studies have suggested that calcium supplements either decrease heart disease risk or have no effect on heart disease risk.

However, the medical profession has been slow to take note of this trend. Most medical societies and health professionals have focused on earlier studies and are still recommending that their patients get calcium from food rather than from supplements.

A recent meta-analysis of 12 double-blinded randomized clinical trials with 87,899 participants comparing the effect of a calcium supplement versus a placebo on heart disease outcomes has just been published. This study found no effect of calcium supplementation on:

  • Heart attack.
  • Stroke.
  • Heart failure.
  • Cardiovascular mortality.
  • All-cause mortality.

The authors of the study concluded, “Calcium supplementation was not associated with myocardial infraction [heart attack], stroke, heart failure, and cardiovascular/all-cause mortality.

For more details and advice on whether you should follow your doctor’s recommendations for calcium supplementation read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 _____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

____________________________________________________________________

About The Author

Dr. Steve ChaneyDr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

 

What Can Twins Tell Us About Diet?

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What Are The Pros And Cons Of Twin Studies? 

Author: Dr. Stephen Chaney 

Why is the advice on healthy diets so confusing? One blog claims the vegan diet is best. Another says it is the keto diet is best. The Mediterranean diet is popular, but other experts claim the DASH or MIND diet might be better. Blogs champion diets ranging from the familiar to downright weird.

If you try to keep up with the science, it seems like the science is constantly changing. Each week you see headlines saying the latest study shows diet “X” is best – and “X” keeps changing. Why is that? Why do studies on healthy diets keep coming up with conflicting conclusions?

I have discussed the strengths and weaknesses of clinical studies and why they provide conflicting results in detail in previous issues of “Health Tips From the Professor”. However, one factor I have not discussed in detail is the effect of genetics on how we utilize foods, something called nutrigenomics.

Simply put, we are all genetically different. The way we utilize foods is different. The effect that foods have on our bodies is different. I have touched on that briefly in a previous article discussing individual difference in blood sugar response to various foods. But that is just one of many examples.

We do not yet know enough about gene-nutrient interactions to use genomic data to accurately predict which diets are best. Again, I have covered that topic in a previous issue of “Health Tips From the Professor”. However, we do know that genetic differences have a big influence on which diet is best for us. And most clinical studies on diets do not even attempt to take genetic differences into account.

That is where twin studies come in. Identical twins (monozygotic twins) have an identical genetic makeup and usually have an identical environment until they become adults. So, when I saw an identical twin study (MJ Landry et al, JAMA Network Open, 6(11):e2344457, 2023) comparing a vegan diet (only plant foods) with an omnivorous diet (both animal and plant foods), I wanted to review it and share it with you.

How Was The Study Done? 

Clinical StudyIdentical twins were recruited from the Stanford Twin Registry. Twenty-two identical twin pairs were chosen for this study. Their characteristics were average age = 40, BMI = 26% (moderately overweight), sex = 77% female, ethnicity = 73% white, followed by an approximately equal representation of Asian, black, multiracial, and Pacific Islander.

One unanticipated characteristic of this group of twins was that 70% of them still lived together and cooked together, so their environment was also very similar.

One twin of each pair was put on a healthy vegan diet and the other on a healthy omnivorous diet for 8 weeks. Both diets were designed by dietitians. The diets emphasized fruits, vegetables, and whole grains while limiting added sugars and refined grains.

Both diets were healthier than the diets the twins were eating prior to the study. Finally, the participants were not told how much to eat, and were not instructed to lose weight.

For the first four weeks the participants were provided with all their meals by a nationwide food delivery company. The participants were also provided with training on purchasing and preparing healthy foods for their diet. This prepared them for the last 4 weeks of the study in which they purchased and prepared their own meals.

Participants visited the Stanford Clinical and Translational Science Research Unit at the beginning of the study and at the end of weeks 4 and 8 for weight measurement and a fasting blood draw.

Adherence to the diets was measured by a series of unannounced interviews to administer a 24-hour dietary recall questionnaire. These were scheduled for the weeks they visited the clinic.

What Can Twins Tell Us About Diet? 

TwinsEven though the sample size was small, there were three statistically significant results.

  • LDL-cholesterol was reduced by 12% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet.
  • The fasting insulin level was reduced by 21% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet. This suggests the twin on the vegan diet was experiencing improved blood sugar control after just 8 weeks.
  • The twin on the vegan diet lost 4 pounds in 8 weeks, while weight remained the same for the twin on the omnivorous diet. This occurred even though neither twin was instructed to eat less nor to lose weight. It is most likely a consequence of the lower caloric density of the vegan diet (See my discussion of caloric density in last week’s issue of “Health Tips From the Professor”.
  • The changes in LDL-cholesterol and fasting insulin were remarkable because none of the twins in this study had elevated LDL-cholesterol or problems with blood sugar control at the beginning of the study.

The authors of this study concluded, “In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their patients.”

[Let me decipher the term cardiometabolic for you. The decrease in LDL-cholesterol is associated with heart health – the cardio portion of the term. The decrease in fasting insulin is associated with decreased risk of diabetes. Since diabetes is considered a metabolic disease, this is the metabolic portion of the term.]

Were There Any Downsides To The Vegan Diet? 

thumbs down symbolThis study also highlighted two well-known limitations of vegan diets.

  • Although the differences were not statistically significant, the authors expressed concern that vitamin B12 intake was less for twins on the vegan diet than twins on the omnivorous diet even though the vegan diet was designed by dietitians.

The authors noted that B12 deficiency among vegans is well known, and said, “Long-term vegans are typically encouraged to take a cyanocobalamin (vitamin B12) supplement.

  • Although both groups had excellent adherence to their assigned diets, those assigned to the vegan diet expressed a lower satisfaction with the diet, which suggests long-term adherence to the diet after the study ended was unlikely.

The authors said, “Although our findings suggest that vegan diets offer a protective cardiometabolic advantage compared with a healthy omnivorous diet, excluding all meats and/or dairy products may not be necessary because research suggests that cardiometabolic benefits can be achieved with modest reduction in animal foods and increases in healthy plant-based foods compared with typical diets.”

“We believe that lower dietary satisfaction in the vegan group may have been attributable to the strictness of the vegan diet…Some people may find a less restrictive diet preferable for LDL-cholesterol-lowering effects.”

I concur.

What Are The Pros And Cons Of Twin Studies? 

pros and consThe Pros are obvious. Most dietary studies cannot take genetic differences into account and have difficulty accounting for environmental differences. In this study genetics was identical for each twin pair and their environment was very similar. It offers a unique advantage over other studies.

But the strength of this study is also its greatest weakness. Because the general population is genetically and environmentally diverse, it is difficult to extrapolate the results to the general population.

If this were the only study to show cardiometabolic benefits of a plant-based diet, it would simply be an interesting observation.

  • But there are several studies showing that the vegan diet is associated with lower weight and reduced risk of heart disease and diabetes.
  • And there are dozens of studies showing that primarily plant-based omnivorous diets reduce the risk of heart disease and diabetes.

This study is fully consistent with those studies.

The Bottom Line 

A recent study put identical twins on either a healthy vegan diet (only plant foods) or a healthy omnivorous diet (both animal and plant foods) for 8 weeks. At the end of 8 weeks:

  • LDL-cholesterol was reduced by 12% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet.
  • The fasting insulin level was reduced by 21% for the twin on the vegan diet, while it remained unchanged for the twin on the omnivorous diet. This suggests the twin on the vegan diet was experiencing improved blood sugar control after just 8 weeks.
  • The twin on the vegan diet lost 4 pounds in 8 weeks, while weight remained the same for the twin on the omnivorous diet. This occurred even though neither twin was instructed to eat less or to lose weight. It is most likely a consequence of the lower caloric density of the vegan diet.
  • The changes in LDL-cholesterol and fasting insulin were remarkable because none of the twins in this study had elevated LDL-cholesterol or problems with blood sugar control at the beginning of the study.

The authors of this study concluded, “In this randomized clinical trial of the cardiometabolic effects of omnivorous vs vegan diets in identical twins, the healthy vegan diet led to improved cardiometabolic outcomes compared with a healthy omnivorous diet. Clinicians can consider this dietary approach as a healthy alternative for their patients.”

For more information on the pros and cons of this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 _____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

_______________________________________________________________________

 About The Author

Dr. Steve ChaneyDr. Chaney has a BS in Chemistry from Duke University and a PhD in Biochemistry from UCLA. He is Professor Emeritus from the University of North Carolina where he taught biochemistry and nutrition to medical and dental students for 40 years.  Dr. Chaney won numerous teaching awards at UNC, including the Academy of Educators “Excellence in Teaching Lifetime Achievement Award”. Dr Chaney also ran an active cancer research program at UNC and published over 100 scientific articles and reviews in peer-reviewed scientific journals. In addition, he authored two chapters on nutrition in one of the leading biochemistry text books for medical students.

For the past 35 years Dr. Chaney and his wife Suzanne have been helping people improve their health holistically through a combination of good diet, exercise, weight control and appropriate supplementation.

Which Diets Are Heart Healthy?

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Which Diet Is Best For You?

Author: Dr. Stephen Chaney 

strong heartThe top 3 claims the advocates of every popular diet make are:

  • It will help you lose weight.
  • It reduces your risk of diabetes.
  • It reduces your risk of heart disease.

The truth is any restrictive diet helps you lose weight. And when you lose weight, you improve blood sugar control. Which, of course, reduces your risk of developing diabetes.

But what about heart disease? Which diets are heart healthy? When it comes to heart disease the claims of diet advocates are often misleading. That’s because the studies these advocates use to support their claims are often poor quality studies. Many of these studies:

  • Look at markers of heart disease risk rather than heart disease outcomes. Markers like LDL cholesterol, triglycerides, c-reactive protein, etc. are only able to predict possible heart disease outcomes. To really know which diets are heart healthy you have to measure actual heart disease outcomes such as heart attacks, stroke, and cardiovascular deaths.
  • Are too short to provide meaningful results. Many of these studies last only a few weeks. You need much longer to measure heart disease outcomes.
  • Are too small to provide statistically significant results. You need thousands of subjects to be sure the results you are seeing are statistically significant.
  • Have not been confirmed by other studies. The Dr. Strangeloves of the world like to “cherry pick” the studies that support the effectiveness of their favorite diet. Objective scientists know that any individual study can be wrong. So, they look for consensus conclusions from multiple studies.

A recent study (G Karam et al, British Medical Journal, 380: e072003, 2023) avoided all those pitfalls. The investigators conducted a meta-analysis of 40 high-quality clinical studies with 35,548 participants to answer the question, “Which diets are heart healthy?”

How Was The Study Done?

Clinical StudyThe authors started by searching all major databases of clinical studies for studies published on the effect of diets on heart disease outcomes through September 2021.

They then performed a meta-analysis of the data from all studies that:

  • Compared the effect of a particular diet to minimal dietary intervention (defined as not receiving any advice or receiving dietary information such as brochures or brief advice from their clinician with little or no follow-up).
  • Looked at heart disease outcomes such as all cause mortality, cardiovascular mortality, non-fatal heart attacks, stroke, and others.
  • Lasted for at least 9 months (average duration = 3 years).
  • Were high-quality studies.

Using these criteria:

  • They identified 40 studies with 35,548 participants for inclusion in their meta-analysis.
    • From those 40 studies, they identified 7 diet types that met their inclusion criteria (low fat (18 studies), Mediterranean (12 studies), very low fat (6 studies), modified fat (substituting healthy fats for unhealthy fats rather than decreasing fats, 4 studies), combined low fat and low sodium (3 studies), Ornish (3 studies), Pritikin (1 study).

One weakness of meta-analyses is that the design of the studies included in the meta-analysis is often different. Sometimes they don’t fit together well. So, while the individual studies are high-quality, a combination of all the studies can lead to a conclusion that is low quality or moderate quality.

Finally, the data were corrected for confounding factors such as obesity, exercise, smoking, and medication use.

Which Diets Are Heart Healthy?

Now that you understand the study design, we are ready to answer the question, “Which diets are heart healthy?” Here is what this study found:

Compared to minimal intervention,

  • The Mediterranean diet decreased all cause mortality by 28%, cardiovascular mortality by 45%, stroke by 35%, and non-fatal heart attacks by 52%.
  • Low fat diets decreased all cause mortality by 16% and non-fatal heart attacks by 23%. The effect of low fat diets on cardiovascular mortality and stroke was not statistically significant in this meta-analysis.
    • For both the Mediterranean and low fat diets, the heart health benefits were significantly better for patients who were at high risk of heart disease upon entry into the study.
    • The evidence supporting the heart health benefits for both diets was considered moderate quality evidence for this meta-analysis. [Remember that the quality of any conclusion in a meta-analysis is based on both the quality of evidence of the individual studies plus how well the studies fit together in the meta-analysis.]
  • While the percentage of risk reduction appears to be different for the Mediterranean and low fat diets, the effect of the two diets on heart health was not considered significantly different in this study.
  • The other 5 diets provided little, or no benefit, compared to the minimal intervention control based on low to moderate quality evidence.

The authors concluded, “This network meta-analysis found that Mediterranean and low fat dietary programs probably reduce the risk of mortality and non-fatal myocardial infarction [heart attacks] in people at increased cardiovascular risk. Mediterranean dietary programs are also likely to reduce the risk of stroke. Generally, other dietary programs were not superior to minimal intervention.”

Which Diet Is Best For You?

confusionThe fact that this study found both the Mediterranean diet and low fat diets to be heart healthy is not surprising. Numerous individual studies have found these diets to be heart healthy. So, it is not surprising when the individual studies were combined in a meta-analysis, the meta-analysis also concluded they were heart healthy. However, there are two important points I would like to make.

  • The diets used in these studies were designed by trained dietitians. That means the low fat studies did not use Big Food, Inc’s version of the low fat diet in which fatty foods are replaced with highly processed foods. In these studies, fatty foods were most likely replaced with whole or minimally processed foods from all 5 food groups.
  • The Mediterranean diet is probably the most studied of current popular diets. From these studies we know the Mediterranean diet improves brain health, gut health, and reduces cancer risk.

As for the other 5 diets (very low fat, modified fat, low fat and low sodium, Ornish, and Pritikin), I would say the jury is out. There is some evidence that these diets may be heart healthy. But very few of these studies were good enough to be included in this meta-analysis. Clearly, more high-quality studies are needed.

Finally, you might be wondering why other popular diets such as paleo, low carb, and very low carb (Atkins, keto, and others) were left out of this analysis. All I can say is that it wasn’t by design.

The authors did not select the 7 diets described in this study and then search for studies testing their effectiveness. They searched for all studies describing the effect of diets on heart health. Once they identified 40 high-quality studies, they grouped the diets into 7 diet categories.

I can only conclude there were no high-quality studies of paleo, low carb, or very low carb diets that met the criteria for inclusion in this meta-analysis. The criteria were:

  • The effect of diet on heart health must be compared to a control group that received no or minimal dietary advice.
  • The study must measure heart disease outcomes such as all cause mortality, cardiovascular mortality, non-fatal heart attacks, and stroke.
  • The study must last at least 9 months.
  • The study must be high-quality.

Until these kinds of studies are done, we have no idea whether these diets are heart healthy or not.

So, what’s the takeaway for you? Which diet is best for you? Both low fat diets and the Mediterranean diet are heart healthy provided the low fat diet consists of primarily whole or minimally processed foods. Which of these two diets is best for you depends on your food preferences.

The Bottom Line 

Many of you may have been warned by your doctor that your heart health is not what it should be. Others may be concerned because you have a family history of heart disease. You want to know which diets are heart healthy.

Fortunately, a recent study answered that question. The authors performed a meta-analysis of 40 high-quality studies that compared the effect of various diets with the effect of minimal dietary intervention (doctors’ advice or diet brochure) on heart disease outcomes.

From this study they concluded that both low fat diets and the Mediterranean diet probably reduce mortality and the risk of non-fatal heart attacks, and that the Mediterranean diet likely reduces stroke risk.

Other diets studied had no significant effect on heart health in this study. That does not necessarily mean they are ineffective. But it does mean that more high-quality studies are needed before we can evaluate their effect on heart health.

So, what’s the bottom line for you? Both low fat diets and the Mediterranean diet are heart healthy provided the low fat diet consists of primarily whole or minimally processed foods Which of these two diets is best for you depends on your food preferences.

For more information on this study, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

___________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

Which Diets Are Heart Healthy?

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What Does A Heart Healthy Diet Look Like?

Author: Dr. Stephen Chaney 

heart attacksHeart disease is a big deal. According to the CDC, “Heart disease is the leading cause of death for men, women, and people of most racial and ethnic groups in the United States. One person dies every 33 seconds in the United States from cardiovascular disease. About 695,000 people in the United States died from heart disease in 2021 – that’s 1 in every 5 deaths”.

This doesn’t have to happen. According to the Cleveland Clinic, “90 percent of heart disease is preventable through healthier diet, regular exercise, and not smoking”. For this issue of “Health Tips From the Professor”, I will focus on the role of diet on heart health.

The problem is many Americans are confused. They don’t know what a heart-healthy diet is. There is so much conflicting information on the internet.

Fortunately, the American Heart Association has stepped in to clear up the confusion.

In 2021 they reviewed hundreds of clinical studies and published “Evidence-Based Dietary Guidance to Promote Cardiovascular Health”.

And recently they have published a comprehensive review (CD Gardner et al, Circulation, 147: 1715-1730, 2023) of how well popular diets align with their 2021 dietary guidelines.

I will cover both publications below. But first I want to address why Americans are so confused about which diets reduce heart disease risk.

Why Are Americans Confused About Diet And Heart Disease Risk?

I should start by addressing the “elephant in the room”.

  • As I discussed in last week’s “Health Tips From the Professor” article, Big Food Inc has seduced us. They have developed an unending supply of highly processed foods that are cheap, convenient, easy to prepare, and fulfill all our cravings. These foods are not heart-healthy, but they make up 73% of our food supply.

The Institute of Medicine, the scientific body that sets dietary standards, states that a wide range of macronutrient intakes are consistent with healthy diets. Specifically, they recommend carbohydrate intake at 45% to 65%, fat intake at 20% to 35%, and protein intake at 10% to 35% of total calories. (Of course, they are referring to healthy carbohydrates, fats, and proteins.)

The authors of this article pointed to several reasons why Americans have been misled about heart-healthy diets.

  • Many of the most popular diets fall outside of the “Acceptable Macronutrient Range”.
  • Many popular diets exclude heart-healthy food groups.

And, the words of the authors,

  • “Further contributing to consumer misunderstanding is the proliferation of diet books, [and] blogs [by] clinicians with limited understanding of what the dietary patterns entail and the evidence base for promoting cardiometabolic health.” I call these the Dr. Strangeloves of our world.

What Does A Heart Healthy Diet Look Like?

Let me start by sharing the American Heart Association’s 10 “Evidence-Based Dietary Guidelines to Promote Cardiovascular Health.

#1: Adjust energy intake and expenditure to achieve and maintain a healthy body weight
#2: Eat plenty of vegetables and fruits; choose a wide variety
#3: Choose foods made mostly with whole grains rather than refined grains
#4: Choose healthy sources of protein
Mostly from plants (beans, other legumes, and nuts)
Fish and seafood
Low-fat or fat-free dairy products instead of full-fat dairy products
If meat or poultry are desired, choose lean cuts and avoid processed forms
#5. Use liquid plant oils (olive, safflower, corn) rather than animal fats (butter and lard) and tropical oils (coconut and palm kernel)
#6. Use minimally processed foods instead of highly processed foods
#7: Minimize intake of beverages and foods with added sugars
#8: Choose and prepare foods with little or no salt
#9: If you do not drink alcohol, do not start; if you choose to drink alcohol, limit intake
#10: Adhere to this guidance regardless of where food is prepared or consumed

Here are my comments on these guidelines:

  • If you have been reading my “Health Tips From the Professor” blog for a while, you probably realize that these aren’t just guidelines to promote heart health. These guidelines also reduce the risk of diabetes, cancer, inflammatory diseases, and much more.
  • If you have read my post on coconut oil, you will know that I have a minor disagreement with the AHA recommendation to avoid it. There is no long-term evidence that coconut oil is bad for the heart. But there is also no long-term evidence that it is good for the heart. My recommendation is to use it sparingly.
  • And you probably know there has been considerable discussion recently about whether full fat dairy is actually bad for the heart. In my most recent review of the topic, I concluded that if full fat dairy is heart healthy, it is only in the context of a primarily plant-based diet and may only be true for fermented dairy foods like unpasteurized yogurt and kefir.
  • Finally, guideline 10 may need some translation. Basically, this guideline is just asking how easy it is to follow the diet when you are away from home.

Which Diets Are Heart Healthy?

confusionIn evaluating how well diets adhered to the American Heart Association guidelines the authors ignored item 1 (energy intake) because most of the diets they evaluated did not provide any guidelines on how many calories should be consumed.

Each diet was given a score between 0 (Fail) and 1 (A+) for each of the other 9 guidelines by a panel of experts. The points for all 9 guidelines were added up, giving each diet a rating of 0 (worst) to 9 (best). Finally, a score of 9 was assigned 100%, so each diet could be given a percentage score for adherence to heart-healthy guidelines.

Here are the results:

Tier 1 diets (the most heart healthy diets) received scores of 86% to 100%. Going from highest (100%) to lowest (86%), these diets were:

  • DASH, Nordic, Mediterranean, Pescetarian (vegetarian diets that allow fish), and Ovo-Lacto Vegetarian (vegetarian diets that allow dairy, eggs, or both).
  • You will notice that these are all primarily plant-based diets.

Tier 2 diets were Vegan and other low-fat diets (TLC, Volumetrics). They both received scores of 78%.

  • The Vegan diet received 0 points for category 10 (ease of following the diet when eating out). It was also downgraded in category 7 for not having clear guidance for the use of salt when preparing foods.
  • The other low-fat diets were downgraded in categories 7, 10, and 5 (use of tropical oils).

Tier 3 diets received scores of 64% to 72%. They included very-low fat diets (<10% fat, very strict vegan diets) and low-carb diets (Zone, South Beach, Low-Glycemic Index).

  • They received 0 points for category 10 and were downgraded for eliminating heart-healthy food groups (liquid plant oils for the very low-fat diets, and fruits, vegetables, whole grains, and plant proteins for the low-carb diets).

Tier 4 diets (the least heart healthy diets) were the Paleo diet with a score of 53% and very low-carb diets (Atkins and Ketogenic) with a score of 31%.

  • The Paleo diet received 0 points for categories 10, 3 (choose whole grains), and 5 (using liquid plant oils rather than animal fats or tropical oils). It was also downgraded for lack of healthy plant-based protein sources.
  • The very low-carb diets were the least heart healthy. They received 0 points for categories 2 (eat plenty of fruits and vegetables), 3 (choose whole grains), 3 (healthy protein sources), 5 (use liquid plant oils instead of animal fats), 7 (minimize salt consumption), and 10 (ease of following the diet away from home).

The authors concluded, “Numerous [dietary] patterns [are] strongly aligned with 2021 American Heart Association Dietary Guidance (ie, Mediterranean, DASH, pescetarian, vegetarian) [and] can be adopted to reflect personal and cultural preferences and budgetary constraints.

Thus, optimal cardiovascular health would be best supported by developing a food environment that supports adherence to these patterns wherever food is prepared or consumed.”

Given our current food environment that last statement is wildly optimistic. But at least you have the information needed to make the best food choices for you and your family

The Bottom Line 

In 2021 the American Heart Association published 10 guidelines for evaluating heart-healthy diets. A recent study looked at how well popular diets adhered to those guidelines. The authors separated the diets into four categories (tiers) based on how heart-healthy they were. The results were not surprising:

  • Tier 1 diets (the most heart healthy diets) were DASH, Nordic, Mediterranean, Pescetarian (vegetarian diets that allow fish), and Ovo-Lacto Vegetarian (vegetarian diets that allow dairy, eggs, or both).
  • Tier 2 diets were Vegan and other low-fat diets (TLC, Volumetrics).
  • Tier 3 diets included very-low fat diets (<10% fat, very strict vegan diets) and low-carb diets (Zone, South Beach, Low-Glycemic Index).
  • Tier 4 diets (the least heart healthy diets) were the Paleo diet and very low-carb diets (Atkins and Ketogenic).

The authors concluded, “Numerous [dietary] patterns [are] strongly aligned with 2021 American Heart Association Dietary Guidance (ie, Mediterranean, DASH, pescetarian, vegetarian) [and] can be adopted to reflect personal and cultural preferences and budgetary constraints.

Thus, optimal cardiovascular health would be best supported by developing a food environment that supports adherence to these patterns wherever food is prepared or consumed.”

Given our current food environment that last statement is wildly optimistic. But at least you have the information needed to make the best food choices for you and your family.

For more information on this study, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

Are Easter Eggs Bad For You?

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Clearing Up The Eggfusion 

Author: Dr. Stephen Chaney

The Easter Bunny will be here soon bringing beautifully decorated eggs for all the children. But wait. Aren’t eggs bad for us? Should we really be encouraging our kids to eat Easter eggs? Maybe we should encourage them to eat Easter candy instead (just kidding).

What is the truth about eggs on our health? Perhaps it’s time for the professor to clear up the “eggfusion” (That’s short for egg confusion). Let me start with a brief historical summary:

  • First there were the warnings that eggs were bad for your heart because egg yolks contained cholesterol, and cholesterol was to be avoided at all costs.
  • Then experts decided that dietary cholesterol wasn’t all that bad for you. It was saturated fats, obesity, and lack of exercise that raised “bad” (LDL) cholesterol levels in your bloodstream.
  • That was followed by several US studies suggesting that eggs in moderation (one per day) did not affect your risk of heart disease.
  • Then a major study claimed that an egg a day actually lowered your risk of heart disease.

Now, the most recent headlines claim that eggs increase your risk of heart disease, and you should avoid them. No wonder you are experiencing eggfusion. Let me review the latest study and put it into perspective by comparing it to previous studies. Let me clear up the eggfusion.

But let me warn you. This is a bit complex, as the truth often is. When I try to explain the contradictions between major studies on egg consumption and heart health, I think the best analogy might be the tale of the blind men trying to tell what an elephant was like by touching different parts of the elephant. None of them could provide an accurate description because none of them could see the whole elephant.

We need to look at the “whole elephant” to see what these studies missed.

How Was The Study Done?

Heart Disease StudyThis study (WW Zhong et al, JAMA, 321: djw322, 2017) combined the data from 6 clinical trials in the United States that assessed dietary intake and measured cardiovascular health outcomes. In all, these studies included 29,615 adults who were followed for an average of 17.5 years.

The diet of the participants was assessed upon entry into each of the clinical trials. The primary variables derived from the dietary information were cholesterol and egg consumption. Diet was not assessed at later times in these studies.

The primary outcomes measured were heart disease and all-cause mortality. In this study heart disease was an umbrella term that included fatal and non-fatal heart attacks, stroke, heart failure, and death from other heart-related causes.

Do Eggs Increase Heart Disease Risk?

heart attacksHere are the main findings from this study.

  • Each additional half an egg consumed per day (which is equivalent to 3-4 eggs per week) was associated with a:
    • 6% increased risk of heart disease. While that doesn’t sound like much, the increased risk was over 13% for one egg per day and almost 27% for two eggs per day.
  • The increased heart disease risk associated with one half egg per day was greater for:
    • Women (13% increase) than men (3% increase).
    • People who already had high blood cholesterol (7% increase), not people who already had low cholesterol levels (0% increase). This suggests that the effect of eggs on heart disease risk primarily affects people who are already having trouble controlling their blood cholesterol levels – either due to genetics or due to diet & lifestyle.

Of course, the question is whether it was the eggs that increased the risk of heart disease or was it something else in the diet. This study attempted to answer that question by systematically subtracting out other variables that affect heart disease risk to see whether that correction eliminated the association between egg consumption and heart disease risk. When this was done:

  • The association between egg consumption and heart disease risk disappeared after correcting for dietary cholesterol intake.
  • The association between egg consumption and heart disease risk remained significant after correcting for other components of the diet, such as fats, animal protein, fiber, sodium, or overall “diet quality”. There were 3 main measures of diet quality.
    • The Med diet score measures how closely the diet resembles the Mediterranean diet.
    • The DASH diet score measures how closely the diet resembles the DASH diet.
    • The Healthy Eating Index (HEI) measures how closely the diet aligns with the USDA Dietary Guidelines For Americans. Basically, the HEI recommends a whole food diet containing foods from all 5 food groups with a heavy emphasis on fruits, vegetables, whole grains, and legumes. It also recommends limiting saturated and trans fats, added sugars, and sodium.

In simple terms the authors concluded that the effect of eggs on heart disease risk was primarily due to their cholesterol content and was not influenced by other components of the overall diet. [I will revisit this conclusion latter.]

What Are The Strengths And Weaknesses Of The Study?

SkepticThe strengths are obvious. This was a very large study (29,615 participants) and the people enrolled in the study were followed for a long time (an average of 17.5 years). The primary variables in the study (cholesterol consumption, egg consumption, heart disease, and all-cause mortality) were accurately measured in each of the clinical trials included in the study.

However, there were some significant weaknesses as well:

  • Cholesterol and egg consumption were only measured by a single dietary survey when people entered the study. This study assumes they did not change over the course of the study. That is very unlikely. Both cholesterol intake and egg consumption in the US population have waxed and waned over the years, in part due to variations in dietary guidelines.
  • The measurements of diet quality used were based on US and European food preferences. That is significant because the only studies showing that egg consumption lowers heart disease risk were performed in China and Japan, where the diet is closer to semi-vegetarian than to US or European diets.

Are Easter Eggs Bad For You?

thumbs down symbolThis is very large, well designed study that combines the data from 6 clinical trials spanning the years 1974 to 2013.

The strongest conclusions from the study are:

  • In the context of a Western diet (the US diet) egg consumption slightly increases your risk developing heart disease. The increased risk is ~6% for 3-4 eggs/week, ~13% for 1 egg per day, and ~27% for two eggs per day.
  • The increased risk of heart disease appears to be almost entirely due to the cholesterol content of eggs.

The significance of this study needs to be weighed in the context of:

  • Recent studies in the US and Europe showing eggs do not increase heart disease risk.
  • Studies in China and Japan (where the diets can best be described as semi-vegetarian) showing that eggs decrease heart disease risk.

The significance of this study also needs to be weighed in the context of:

  • Studies showing that obesity, saturated fat, and physical inactivity have bigger effects on serum cholesterol levels and heart disease risk than dietary cholesterol from foods like eggs.

What Did This Study Miss?

EggsIf, as this study suggests, the effect of eggs on heart disease risk is due to their cholesterol content, this study (and most previous studies) missed a very important point. The effect of dietary cholesterol on blood cholesterol levels is not strongly affected by the overall composition of the diet. It is affected by the composition of the diet at the time foods containing dietary cholesterol are eaten.

  • The kind of fiber found in certain fruits, vegetables, whole grains, and legumes bind to dietary cholesterol, preventing it from being absorbed as it passes through the intestine.
  • Certain phytonutrients in plant foods affect how dietary cholesterol is utilized by the body.
  • However, to blunt the effect of dietary cholesterol on blood cholesterol levels the fiber and phytonutrient-containing foods must be consumed at the same meal.

Simply put, if your breakfast consists of eggs, sausage, biscuits, and hash browns, the cholesterol in the eggs will likely increase your blood cholesterol level, which in turn increases your risk of heart disease. This will occur even if you eat lots of fruits, vegetables, whole grains, and legumes with your other meals.

If, on the other hand, your breakfast consists of eggs and fiber-rich plant foods like oatmeal and beans, the cholesterol in the eggs will likely have a much smaller effect on your blood cholesterol levels and your heart disease risk.

The fact that previous studies have not looked at what foods were consumed along with the eggs may explain some of the variation in their conclusions about the effect of egg consumption on heart disease risk.

The Professor’s Story

professor owlLet me share my story with you. About 25 years ago, my doctor told me that my cholesterol levels were getting high and wanted to put me on statins. I didn’t take a stain, and I didn’t stop eating eggs for breakfast. I changed breakfast.

Now I soft boil my eggs or fry them in olive oil. I eat them along with oatmeal, which contains a fiber that binds cholesterol, and walnuts, which contain omega-3s and phytonutrients that lower blood cholesterol. I also include whatever fruit is in season. Finally, I take a supplement providing 2 grams of plant stanols and sterols, which blocks cholesterol absorption from the intestine.

My blood cholesterol levels have been low ever since. I have not had to take statins, and I get to enjoy the taste and health benefits of an egg any time I want to. Of course, what worked for me may not work for you. The effect of dietary cholesterol on blood cholesterol levels is also affected by genetics, weight, and fitness, just to name the top three.

Are Easter Eggs Good For You?

thumbs upOnce you get past the cholesterol problem, eggs are a very healthy food.

  1. Studies have shown that egg protein results in improved blood sugar control, better satiety (feeling of fullness), and reduced subsequent food intake in healthy and overweight individuals. In layman’s terms that means egg protein can help you achieve and maintain a healthy weight.

2) Egg yolks are a good source of lutein and zeaxanthin. We think of lutein and zeaxanthin as good for eye health. They also play an important role in protecting against oxidation, inflammation, and atherosclerosis.

3) Egg yolks also contain choline. We think of choline as good for brain and nerves. But, choline and other phospholipids in the yolk also raise HDL levels and enhance HDL function.

4) Eggs are a good source of vitamin A, vitamin D, vitamin B12, riboflavin, selenium and iron.

5) Eggs contain almost twice as much monounsaturated and polyunsaturated fats as saturated fats.

Clearing Up The “Eggfusion”

egg confusion

  1. The latest study suggests that eggs may increase your risk of heart disease, and this is due to their cholesterol content.

2) This study needs to be considered in the context of recent studies in the US showing that egg consumption did not increase heart disease risk and studies in China and Japan showing that egg consumption lowered heart disease risk.

3) It is also important to consider that egg consumption in China and Japan is in the context of a semi-vegetarian diet. This suggests that diet plays a role in determining the effect of egg consumption on heart disease risk.

4) However, if you take this study at face value, there are two things you can do to reduce your risk of heart disease:

  • Reduce dietary cholesterol by avoiding eggs or using egg whites.
    • Eat eggs in moderation along with fiber- and phytonutrient-rich plant foods that negate the effect of dietary cholesterol on blood cholesterol levels. I recommend oatmeal or beans, nuts or seeds, and fiber rich fruits and vegetables. These should be consumed at the same meal to minimize the effect of the cholesterol in the eggs on blood cholesterol levels. As for Easter eggs, they are a perfect addition to a green salad.
    • Eggs are a very healthy food, so I recommend the second option if possible. Get your blood cholesterol levels measured to determine which approach works best for you.

5) Finally, we need to recognize that egg consumption plays a relatively minor role in determining heart disease risk. Other factors play a much larger role in influencing heart disease risk. For example:

    • Smoking, obesity, inactivity, saturated and trans fats significantly increase your risk of heart disease.
    • Omega-3s, antioxidants, and a primarily plant-based diet like the Mediterranean diet significantly decrease your risk of heart disease.

If we wish to reduce our risk of heart disease, this is where we should focus most of our attention. We can minimize the effect of egg consumption on heart disease risk by changing the foods we eat with the eggs. For more information on how to reduce your risk of heart disease, read my books, “Slaying The Food Myths” and “Slaying The Supplement Myths”.

The Bottom Line

1) The latest study suggests that eggs increase your risk of heart disease because of their cholesterol content.

2) This was a very large study. It combined the data from 6 clinical trials spanning the years 1974 to 2013. It followed 29,615 people for an average of 17.5 years. However, it has two significant weaknesses:

  • It only determined cholesterol intake and egg consumption at the time people entered the clinical trials. Both cholesterol intake and egg consumption have waxed and waned considerably over the years covered by these clinical trials.
  • It did not measure what foods were consumed along with the eggs. Foods consumed along with eggs have a strong influence on how much the cholesterol in the eggs influences blood cholesterol levels, which, in turn, influences the effect eggs have on heart disease risk.

3) This study also needs to be considered in the context of recent studies in the US showing that egg consumption did not increase heart disease risk and studies in China and Japan showing that egg consumption lowered heart disease risk.

4) However, if you take this study at face value, there are two things you can do to reduce your risk of heart disease:

  • Reduce dietary cholesterol by avoiding eggs or using egg whites.
  • Eat eggs in moderation along with fiber- and phytonutrient-rich plant foods that negate the effect of dietary cholesterol on blood cholesterol levels. I recommend oatmeal or beans, nuts or seeds, and fiber rich fruits and vegetables. These should be consumed at the same meal to minimize the effect of the cholesterol in the eggs on blood cholesterol levels. As for Easter eggs, they are a perfect addition to a green salad.
  • Eggs are a very healthy food, so I recommend the second option if possible. Get your blood cholesterol levels measured to determine which approach works best for you.

5) Finally, we need to recognize that egg consumption plays a relatively minor role in determining heart disease risk. Other factors play a much larger role in influencing heart disease risk. For example:

  • Smoking, obesity, inactivity, saturated and trans fats significantly increase your risk of heart disease.
  • Omega-3s, antioxidants, and a primarily plant-based diet like the Mediterranean diet significantly decrease your risk of heart disease.

For more information on how to reduce your risk of heart disease, read my books, “Slaying The Food Myths” and “Slaying The Supplement Myths”.

For more details and to learn what the professor does about egg consumption, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

 

 

 

Which Diets Are Best In 2023?

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Which Diet Should You Choose?

Author: Dr. Stephen Chaney

Emoticon-BadMany of you started 2023 with goals of losing weight and/or improving your health. In many cases, that involved choosing a new diet. That was only 6 weeks ago, but it probably feels like an eternity.

For many of you the “bloom” has gone off the new diet you started so enthusiastically in January.

  • Perhaps the diet isn’t working as well as advertised…
  • Perhaps the diet is too restrictive. You are finding it hard to stick with…
  • Perhaps you are always hungry or constantly fighting food cravings…
  • Perhaps you are starting to wonder whether there is a better diet than the one you chose in January…
  • Perhaps you are wondering whether the diet you chose is the wrong one for you…

If you are rethinking your diet, you might want to know which diets the experts recommend. Unfortunately, that’s not as easy as it sounds. The diet world has become just as divided as the political world.

Fortunately, you have an impartial resource. Each year US News & World Report invites a panel of experts with different points of view to evaluate popular diets. They then combine the input from all the experts into rankings of the diets in various categories.

If you are still searching for your ideal diet, I will summarize the US News & World Report’s “Best Diets In 2023”. For the full report, click on this link.

How Was This Report Created?

Expert PanelUS News & World Report recruited a panel of 30 nationally recognized experts in diet, nutrition, obesity, food psychology, diabetes, and heart disease to review the 24 most popular diets.

The diets evaluated are not the same each year. Last year they evaluated the top 40 most popular diets. This year they only reviewed the top 24.

That means some good diets were left off the list. For example, the vegan diet is very healthy, but it is also very restrictive. Very few people follow a pure vegan diet, so it didn’t make the top 24 most popular. However, this year’s list did include several primarily plant-based diets that are more popular with the general public.

The panel is also not the same each year. Some experts are rotated off the panel, and others are added. The experts rate each diet in seven categories:

  • How easy it is to follow.
  • Its ability to produce short-term weight loss.
  • Its ability to produce long-term weight loss.
  • its nutritional completeness.
  • Its safety.
  • Its potential for preventing and managing diabetes.
  • Its potential for preventing and managing heart disease.

They converted the experts’ ratings to scores 5 (highest) to 1 (lowest). They then used these scores to construct eleven sets of Best Diets rankings:

  • Best Diets Overall ranks diets on several different parameters, including whether all food groups are included in the diet, the availability of the foods needed to be on the diet and the use of additional vitamins or supplements. They considered if the diet was evidence-based and adaptable to meet cultural, religious, or other personal preferences. In addition, the criteria also included evaluation of the prep and planning time required for the diet and the effectiveness of the diet for someone who wants to get and stay healthy.
  • Best Plant-Based Diets used the same approach as Best Diets Overall to rank the eight plans emphasizing minimally processed foods from plants that were included in this year’s ratings.
  • Best Commercial Diet ratings used the same approach to rank 15 commercial diet programs that require a participation fee or promote the use of branded food or nutritional products.
  • Best Long-Term Weight-Loss Diet ratings were generated by combining the safety of the rate of weight loss promoted and the likelihood of the plan to result in successful long-term weight loss and maintenance of weight loss.
  • Best Fast Weight-Loss Diets were scored on their effectiveness for someone who wants to lose weight in three months or less.
  • Best Diabetes Diet ratings were calculated equally from the effectiveness of the diet for someone who wants to lower risk factors for diabetes, the nutritional quality of the diet, and research evidence-based support for the diet.
  • Best Heart-Healthy Diet ratings were calculated equally from the effectiveness of the diet for someone who wants to lower risk factors for hypertension and other forms of heart disease, the nutritional quality of the diet, and evidence-based support for the diet.
  • Best Diets for Bone and Joint Health were calculated equally on the effectiveness of the diet for someone who wants to lower their risk factors for inflammation and improve bone and joint health, as well as the nutritional quality and research evidence-based support for the diet.
  • Best Diets for Healthy Eating combines nutritional completeness and safety ratings, giving twice the weight to safety. A healthy diet should provide sufficient calories and not fall seriously short on important nutrients or entire food groups.
  • Easiest Diets to Follow represents panelists’ averaged scores for the relevant lifestyle questions, including whether all food groups are included and if the recommended foods are readily available at the average supermarket.
  • Best Family-Friendly Diets were calculated equally on their adaptability for the whole family, including cultural, religious, and personal preferences, the time required to plan and prep, nutritional value and access to food at any supermarket.

Which Diets Are Best In 2023?

Are you ready? If this were an awards program, I would be saying “Envelop please” and would open the envelop slowly to build suspense.

However, I am not going to do that. Here are the top 3 and bottom 3 diets in each category (If you would like to see where your favorite diet ranked, click on this link.

[Note: I excluded commercial diets from this review. (I have a brief discussion of commercial diets below). If you notice a number missing in my summaries, it is because I eliminated one or more commercial diet from my summary.]

Best Diets Overall 

The Top 3: 

#1: Mediterranean Diet. The Mediterranean diet has been ranked #1 for 6 consecutive years.

#2 (tie): DASH Diet (This diet was designed to keep blood pressure under control, but you can also think of it as an Americanized version of the Mediterranean diet.)

#2 (tie): Flexitarian Diet (A flexible semi-vegetarian diet).

The Bottom 3: 

#20: Keto Diet (A high protein, high fat, very low carb diet designed to achieve ketosis).

#21: Atkins Diet (The granddaddy of the high animal protein, low carb, high fat diets).

#24: Raw Food Diet (A diet based on eating foods that have not been cooked or processed).

Best Plant-Based Diets Overall 

The Top 3: 

#1: Mediterranean Diet.

#2: Flexitarian Diet.

#3: MIND Diet (This diet is a combination of Mediterranean and DASH but is specifically designed to reduce cognitive decline as we age.)

The Bottom 3: 

Since only 8 diets were included in this category, even the bottom 3 are pretty good diets, so I did not include a “list of shame” in this category.

Best Long-Term Weight-Loss DietsWeight Loss

The Top 3: 

#1: DASH Diet

#2 (tie): Volumetrics Diet (A diet based on the caloric density of foods).

#2 (tie): Mayo Clinic Diet (A diet designed to establish lifelong healthy eating habits).

The Bottom 3: 

#22 (tie): Keto Diet.

#22 (tie): Atkins Diet.

#24: Raw Food Diet.

Best Fast Weight-Loss Diets

The Top 3: 

#1: Keto Diet

#2: Atkins Diet

#7 (tie): Mayo Clinic Diet

#7 (tie): South Beach Diet

#7 (tie): Volumetrics Diet

The Bottom 3: 

The diets at the bottom of this list were designed for health and weight maintenance rather than rapid weight loss, so I did not include a “list of shame” in this category.

Best Diabetes Diets

The Top 3: 

#1: DASH Diet

#2: Mediterranean Diet

#3: Flexitarian Diet

The Bottom 3: 

#20: Atkins Diet

#21: Paleo Diet (A diet based on what our paleolithic ancestors presumably ate. It restricts grains and dairy and is heavily meat-based).

#22: Raw Food Diet.

Best Heart-Healthy Diets

Healthy HeartThe Top 3: 

#1: DASH Diet

#2: Mediterranean Diet

#3 (tie): Ornish Diet (A whole food, semi-vegetarian diet designed to promote heart health).

#3 (tie): Flexitarian Diet

The Bottom 3: 

#22 (tie): Raw Foods Diet

#22 (tie): Paleo Diet

#24: Keto Diet

Best Diets for Bone and Joint Health 

The Top 3: 

#1 (tie): DASH Diet

#1 (tie): Mediterranean Diet

#3: Flexitarian Diet

The Bottom 3: 

#21 (tie): Raw Foods Diet

#21 (tie): Paleo Diet

#22: Atkins Diet 

#23: Keto Diet 

Best Diets for Healthy Eating

The Top 3: 

#1: Mediterranean Diet

#2: DASH Diet

#3: Flexitarian Diet

The Bottom 3: 

#22: Keto Diet

#23: Atkins Diet

#24: Raw Foods Diet

Easiest Diets to FollowEasy

The Top 3: 

#1 (tie): Flexitarian Diet

#1 (tie): TLC Diet (This diet was designed by the NIH to reduce cholesterol levels and promote heart health.)

#3 (tie): Mediterranean Diet

#3 (tie): DASH Diet

The Bottom 3: 

#19: Atkins Diet

#20: Keto Diet

#22: Raw Foods Diet

Which Diets Are Best For Rapid Weight Loss?

Happy woman on scaleThere are 2 take-home lessons from the rapid weight loss category:

  1. If you are looking for rapid weight loss, any whole food restrictive diet will do.
    • Last year’s diet analysis included the vegan diet, and both vegan and keto diets ranked near the top of the rapid weight loss category. Keto and vegan diets are both very restrictive, but they are polar opposites in terms of the foods they allow and restrict.
      • The keto diet is a meat heavy, very low carb diet. It restricts fruits, some vegetables, grains, and most legumes.
      • The vegan diet is a very low-fat diet that eliminates meat, dairy, eggs, and animal fats.
    • The Atkins and keto diets toppled this year’s rapid weight loss list, but they were joined by the Mayo Clinic, South Beach, and volumetrics diets. Those diets are also restrictive, but, like the vegan diet, they are very different from the Atkins and keto diets.
    • I did not include commercial diets that rated high on this list, but they are all restrictive in one way or another.

2) Whole food, very low carb diets like Atkins and keto are good for rapid weight loss, but they rank near the bottom of the list for every healthy diet category.

    • If you choose to lose weight on the Atkins or keto diets, switch to a healthier diet once you reach your desired weight loss.

Which Diet Should You Choose?

Food ChoicesWith rapid weight loss out of the way, let’s get back to the question, “Which Diet Should You Choose?” My recommendations are:

1) Choose a diet that fits your needs. That is one of the things I like best about the US News & World Report ratings. The diets are categorized. If your main concern is diabetes, choose one of the top diets in that category. If your main concern is heart health… You get the point.

2) Choose diets that are healthy and associated with long term weight loss. If that is your goal, you will notice that primarily plant-based diets top these lists. Meat-based, low carb diets like Atkins and keto are near the bottom of the lists.

  • “Why is that?”, you might ask? The answer is simple. And it’s not that all 30 experts were prejudiced against low carb diets. It’s that the major primarily plant-based diets like Mediterranean, DASH, and flexitarian are backed by long-term clinical studies showing they are healthy and significantly reduce the risk of diabetes, heart disease, and other chronic diseases.
  • On the other hand, there are no long-term studies showing the Atkins and keto diets are healthy long term. And since the Atkins diet has been around for more than 50 years, the lack of clinical evidence that it is healthy long term is damming.

3) Choose diets that are easy to follow. The less-restrictive primarily plant-based diets top this list – diets like Mediterranean, DASH, MIND, and flexitarian. They are also at or near the top of almost every diet category.

4) Choose diets that fit your lifestyle and dietary preferences. For example, if you don’t like fish and olive oil, you will probably do much better with the DASH or flexitarian diet than with the Mediterranean diet.

5) Finally, focus on what you have to gain, rather than on foods you have to give up.

  • On the minus side, none of the diets include sodas, junk foods, and highly processed foods. These foods should go on your “No-No” list. Sweets should be occasional treats and only as part of a healthy meal. Meat, especially red meat, should become a garnish rather than a main course.
  • On the plus side, primarily plant-based diets offer a cornucopia of delicious plant foods you probably didn’t even know existed. Plus, for any of the top-rated plant-based diets, there are websites and books full of mouth-watering recipes. Be adventurous.

What About Commercial Diets?

I chose not to review commercial diets by name, but let me make a few observations.

  • If you look at the gaps in my lists, it should be apparent that several commercial diets rank near the top for fast weight loss, but near the bottom on most healthy diet lists.
  • I do not recommend commercial diets that rely on ready-to-eat, low-calorie, highly processed versions “of your favorite foods”.
    • These pre-packaged meals are expensive. Unless you are a millionaire, you won’t be able to afford these meals for the rest of your life.
    • These pre-packaged meals are not teaching you healthy eating habits that will allow you to keep the weight off.
  • If you wish to spend your hard-earned dollars on a commercial diet, choose a diet that:
    • Relies on whole foods from all 5 food groups.
    • Teaches and provides support for the type of lifestyle change that leads to permanent weight loss.
  • Meal replacement shakes can play a role in healthy weight loss if:
    • They are high quality and use natural ingredients as much as possible.
    • They are part of a holistic lifestyle change program.

The Bottom Line 

For many of you the “bloom” has gone off the new diet you started so enthusiastically in January. If you are rethinking your diet, you might want to know which diets the experts recommend. Unfortunately, that’s not as easy as it sounds. The diet world has become just as divided as the political world.

Fortunately, you have an impartial resource. Each year US News & World Report invites a panel of experts with different points of view to evaluate popular diets. They then combine the input from all the experts into rankings of the diets in various categories. In the article above I summarize the US News & World Report’s “Best Diets In 2023”.

There are probably two questions at the top of your list.

#1: Which diets are best for rapid weight loss? Here are 2 general principles:

  1. If you are looking for rapid weight loss, any whole food restrictive diet will do.

2) If you choose to lose weight on the Atkins or keto diets, switch to a healthier diet once you reach your desired weight loss. Atkins and keto diets are good for rapid weight loss, but they rank near the bottom of the list for every healthy diet category.

#2: Which diet should you choose? Here the principles are:

  1. Choose a diet that fits your needs.

2) Choose diets that are healthy and associated with long term weight loss.

3) Choose diets that are easy to follow.

4) Choose diets that fit your lifestyle and dietary preferences.

5) Finally, focus on what you have to gain, rather than on foods you have to give up.

For more details on the diet that is best for you and my thoughts on commercial diets, read the article above.

Which Supplements Are Good For Your Heart?

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How Should You Interpret This Study? 

Author: Dr. Stephen Chaney 

strong heartFebruary is Heart Health month. So, it is fitting that we ask, “What is the status of heart health in this country?” The American Heart Association just published an update of heart health statistics through 2019 (CW Tsao et al, Circulation, 145: e153-e639, 2022). And the statistics aren’t encouraging. [Note: The American Heart Association only reported statistics through 2019 because the COVID-19 pandemic significantly skewed the statistics in 2020 and 2021].

The Good News is that between 2009 and 2019:

  • All heart disease deaths have decreased by 25%.
  • Heart attack deaths have decreased by 6.6%.
  • Stroke deaths have decreased by 6%.

The Bad News is that:

  • Heart disease is still the leading cause of death in this country.
  • Someone dies from a heart attack every 40 seconds.
  • Someone dies from a stroke every 3 minutes.

Diet, exercise, and weight control play a major role in reducing the risk of heart disease. Best of all, they have no side effects. They represent a risk-free approach that each of us can control.

But is there something else? Could supplements play a role? Are supplements hype or hope for a healthy heart?

All the Dr. Strangeloves in the nutrition space have their favorite heart health supplements. They claim their supplements will single-handedly abolish heart disease (and help you leap tall buildings in a single bound).

On the other hand, many doctors will tell you these supplements are a waste of money. They don’t work. They just drain your wallet.

It’s so confusing. Who should you believe? Fortunately, a recent study (P An et al, Journal of the American College of Cardiology, 80: 2269-2285, 2022) has separated the hype from the hope and tells us which “heart-healthy” supplements work, and which don’t.

How Was This Study Done?

Clinical StudyThis was a major clinical study carried out by researchers from the China Agricultural University and Brown University in the US. It was a meta-analysis, which means it combined the data from many published clinical trials.

The investigators searched three major databases of clinical trials to identify:

  • 884 randomized, placebo-controlled clinical studies…
  • Of 27 types of micronutrients…
  • With a total of 883,627 patients…
  • Looking at the effectiveness of micronutrient supplementation lasting an average of 3 years on either…
    • Cardiovascular risk factors like blood pressure, total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides…or…
    • Cardiovascular outcomes such as coronary heart disease (CHD), heart attacks, strokes, and deaths due to cardiovascular disease (CVD) and all causes.

[Note: Coronary heart disease (CHD) refers to build up of plaque in the coronary arteries (the arteries leading to the heart). It is often referred to as heart disease and can lead to heart attacks (myocardial infarction). Cardiovascular disease (CVD) is a more inclusive term that includes coronary heart disease, stroke, congenital heart defects, and peripheral artery disease.]

The investigators also included an analysis of the quality of the data in each of the clinical studies and rated the evidence of each of their findings as high quality, moderate quality, or low quality.

Which Supplements Are Good For Your Heart?

The top 3 heart-healthy supplements in this study were:

Omega-3s And Heart DiseaseOmega-3 Fatty Acids:

  • Increased HDL cholesterol and decreased triglycerides, both favorable risk factors for heart health.
  • Deceased risk of heart attacks by 15%, all CHD events by 14%, and CVD deaths by 7% (see definitions of CHD and CVD above).
  • The median dose of omega-3 fatty acids in these studies was 1.8 g/day.
  • The evidence was moderate quality for all these findings.

Folic Acid:

  • Decreased LDL cholesterol (moderate quality evidence) and decreased blood pressure and total cholesterol (low quality evidence).
  • Decreased stroke risk by 16% (moderate quality evidence).

Coenzyme Q10:

  • Decreased triglycerides (high quality evidence) and reduced blood pressure (low quality evidence).
  • Decreased the risk of all-cause mortality by 32% (moderate quality evidence).
  • These studies were performed with patients diagnosed with heart failure. Coenzyme Q10 is often recommended for these patients, so the studies were likely performed to test the efficacy of this treatment.

There were three micronutrients (vitamin C, vitamin E, and vitamin D) that did not appear to affect heart disease outcomes.

Finally, as reported in previous studies, β-carotene increased the risk of stroke, CVD mortality, and all-cause mortality.

In terms of the question I asked at the beginning of this article, this study concluded that:

  • Omega-3, folic acid, and coenzyme Q10 supplements represent hope for a healthy heart.
  • Vitamin C, vitamin E, and vitamin D supplements represent hype for a healthy heart.
  • β-carotene supplements represent danger for a healthy heart.

But these conclusions just scratch the surface. To put them into perspective we need to dig a bit deeper.

How Should You Interpret This Study?

Question MarkIn evaluating the significance of these findings there are two things to keep in mind.

#1: This study is a meta-analysis and meta-analyses have both strengths and weaknesses.

The strength of meta-analyses is that by combining multiple clinical studies they can end up with a database containing 100s of thousands of subjects. This allows them to do two things:

  • It allows the meta-analysis to detect statistically significant effects that might be too small to detect in an individual study.
  • It allows the meta-analysis to detect the average effect of all the clinical studies it includes.

The weakness of meta-analyses is that the design of individual studies included in the analysis varies greatly. The individual studies vary in things like dose, duration, type of subjects included in the study, and much more.

This is why this study rated most of their conclusions as backed by moderate- or low-quality evidence. [Note: The fact that the authors evaluated the quality of evidence is a strength of this study. Most meta-analyses just report their conclusions without telling you how strong the evidence behind those conclusions is.]

#2: Most clinical studies of supplements (including those included in this meta-analysis) have two significant weaknesses.

  • Most studies do not measure the nutritional status of their subjects prior to adding the supplement. If their nutritional status for a particular nutrient was already optimal, there is no reason to expect more of that nutrient to provide any benefit.
  • Most studies measure the effect of a supplement on a cross-section of the population without asking who would be most likely to benefit.

You would almost never design a clinical study that way if you were evaluating the effectiveness of a potential drug. So, why would you design clinical studies of supplements that way?

With these considerations in mind, let me provide some perspective on the conclusions of this study.

Coenzyme Q10:

This meta-analysis found that coenzyme Q10 significantly reduced all-cause mortality in patients with heart failure. This is consistent with multiple clinical studies and a recent Cochrane Collaboration review.

Does coenzyme Q10 have any heart health benefits for people without congestive heart failure? There is no direct evidence that it does, but let me offer an analogy with statin drugs.

Statin drugs are very effective at reducing heart attacks in high-risk patients. But they have no detectable effect on heart attacks in low-risk patients. However, this has not stopped the medical profession from recommending statins for millions of low-risk patients. The rationale is that if they are so clearly beneficial in high-risk patients, they are “probably” beneficial in low-risk patients.

I would argue a similar rationale should apply to supplements like coenzyme Q10.

Omega-3s:

This study found that omega-3 reduced both heart attacks and the risk of dying from heart disease. Most previous meta-analyses of omega-3s and heart disease have come to the same conclusion. However, some meta-analyses have failed to find any heart health benefits of omega-3s. Unfortunately, this has allowed both proponents and opponents of omega-3 use for heart health to quote studies supporting their viewpoint.

However, there is one meta-analysis that stands out from all the others. A group of 17 scientists from across the globe collaborated in developing a “best practices” experimental design protocol for assessing the effect of omega-3 supplementation on heart health. They conducted their clinical studies independently, and when their data (from 42,000 subjects) were pooled, the results showed that omega-3 supplementation decreased:

  • Premature death from all causes by 16%.
  • Premature death from heart disease by 19%.
  • Premature death from cancer by 15%.
  • Premature death from causes other than heart disease and cancer by 18%.

This study eliminates the limitations of previous meta-analyses. That makes it much stronger than the other meta-analyses. And these results are consistent with the current meta-analysis.

Omega-3s have long been recognized as essential nutrients. It is past time to set Daily Value (DV) recommendations for omega-3s. Based on the recommendations of other experts in the field, I think the DV should be set at 500-1,000 mg/day. I take more than that, but this would represent a good minimum recommendation for heart health.

folic acidFolic acid:

As with omega-3s, this meta-analysis reported a positive effect of folic acid on heart health. But many other studies have come up empty. Why is that?

It may be because, between food fortification and multivitamin use, many Americans already have sufficient blood levels of folic acid. For example, one study reported that 70% of the subjects in their study had optimal levels of folates in their blood. And that study also reported:

  • Subjects with adequate levels of folates in their blood received no additional benefit from folic acid supplementation.
  • However, for subjects with inadequate blood folate levels, folic acid supplementation decreased their risk of heart disease by ~15%.

We see this pattern over and over in supplement studies. Supplement opponents interpret these studies as showing that supplements are worthless. But a better interpretation is that supplements benefit those who need them.

The problem is that we don’t know our blood levels of essential nutrients. We don’t know which nutrients we need, and which we don’t. That’s why I like to think of supplements as “insurance” against the effects of an imperfect diet.

Vitamins E and D:

The situation with vitamins E and D is similar. This meta-analysis found no heart health benefit of either vitamin E or D. That is because the clinical studies included in the meta-analysis asked whether vitamin E or vitamin D improved heart health for everyone in the study.

Previous studies focusing on patients with low blood levels of these nutrients and/or at high risk of heart disease have shown some benefits of both vitamins at reducing heart disease risk.

So, for folic acid, vitamin E, and vitamin D (and possibly vitamin C) the take-home message should be:

  • Ignore all the Dr. Strangeloves telling you that these vitamins are “magic bullets” that will dramatically reduce your risk of heart disease.
  • Ignore the naysayers who tell you they are worthless.
  • Use supplementation wisely to make sure you have the recommended intake of these and other essential nutrients.

β-carotene:

This meta-analysis reported that β-carotene increased the risk of heart disease. This is not a new finding. Multiple previous studies have come to the same conclusion.

And we know why this is. There are many naturally occurring carotenoids, and they each have unique heart health benefits. A high dose β-carotene supplement interferes with the absorption of the other carotenoids. You are creating a deficiency of other heart-healthy carotenoids.

If you are not getting lots of colorful fruits and vegetables from your diet, my recommendation is to choose a supplement with all the naturally occurring carotenoids in balance – not a pure β-carotene supplement.

The Bottom Line 

The Dr. Strangeloves in the nutrition space all have their favorite heart health supplements. They claim their supplements will single-handedly abolish heart disease (and help you leap tall buildings in a single bound).

On the other hand, many doctors will tell you these supplements are a waste of money. They don’t work. They just drain your wallet.

It’s so confusing. Who should you believe? Fortunately, a recent study has separated the hype from the hope and tells us which “heart-healthy” supplements work, and which don’t.

This study was a meta-analysis of 884 clinical studies with 883,627 participants. It reported:

  • Omega-3 supplementation deceased risk of heart attacks by 15% and all cardiovascular deaths by 7%.
  • Folic acid supplementation decreased stroke risk by 16%.
  • Coenzyme Q10 supplementation decreased the risk of all-cause mortality in patients with heart failure by 32%.
  • Vitamin C, vitamin E, vitamin D did not appear to affect heart disease outcomes.
  • β-carotene increased the risk of stroke, CVD mortality, and all-cause mortality.

For more details on this study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

What Is The Truth About Low Carb Diets?

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Why Is The Cochrane Collaboration The Gold Standard?

Author: Dr. Stephen Chaney 

low carb dietAtkins, South Beach, Whole30, Low Carb, high Fat, Low Carb Paleo, and Keto. Low carb diets come in many forms. But they have these general characteristics:

  • They restrict carbohydrate intake to <40% of calories.
  • They restrict grains, cereals, legumes, and other carbohydrate foods such as dairy, fruits, and some vegetables.
  • They replace these foods with foods higher in fat and protein such as meats, eggs, cheese, butter, cream, and oils.
  • When recommended for weight loss, they generally restrict calories.

What about the science? Dr. Strangelove and his friends tell you that low carb diets are better for weight loss, blood sugar control, and are more heart healthy than other diets. But these claims are controversial.

Why is that? I have discussed this in previous issues of “Health Tips From The Professor”. Here is the short version.

  • Most studies on the benefits of low carb diets compare them with the typical American diet.
    • The typical American diet is high in fat, sugar and refined flour, and highly processed foods. Anything is better than the typical American diet.
  • Most low carb diets are whole food diets.
    • Any time you replace sodas and highly processed foods with whole foods you will lose weight and improve your health.
  • Most low carb diets are highly structured. There are rules for which foods to avoid, which foods to eat, and often additional rules to follow.
    • Any highly structured diet causes you to focus on what you eat. When you do that, you lose weight. When you lose weight, your health parameters improve.
    • As I have noted before, short term weight loss and improvement in health parameters are virtually identical for the very low carb keto diet and the very low-fat vegan diet.

With all this uncertainty you are probably wondering, “What is the truth about low carb diets?”

A recent study by the Cochrane Collaboration (CE Naude et al, Cochrane Database of Systematic Reviews, 28 January 2022) was designed to answer this question.

The Cochrane Collaboration is considered the gold standard of evidence-based medicine. To help you understand why this is, I will repeat a summary of how the Cochrane Collaboration approaches clinical studies that I shared two weeks ago.

Why Is The Cochrane Collaboration The Gold Standard?

ghost bustersWho you gonna call? It’s not Ghostbusters. It’s not Dr. Strangelove’s health blog. It’s a group called the Cochrane Collaboration.

The Cochrane Collaboration consists of 30,000 volunteer scientific experts from across the globe whose sole mission is to analyze the scientific literature and publish reviews of health claims so that health professionals, patients, and policy makers can make evidence-based choices about health interventions.

In one sense, Cochrane reviews are what is called a “meta-analysis”, in which data from numerous studies are grouped together so that a statistically significant conclusion can be reached. However, Cochrane Collaboration reviews differ from most meta-analyses found in the scientific literature in a very significant way.

Many published meta-analyses simply report “statistically significant” conclusions. However, statistics can be misleading. As Mark Twain said: “There are lies. There are damn lies. And then there are statistics”.

The Cochrane Collaboration also reports statistically significant conclusions from their meta-analyses. However, they carefully consider the quality of each individual study in their analysis. They look at possible sources of bias. They look at the design and size of the studies. Finally, they ask whether the conclusions are consistent from one study to the next. They clearly define the quality of evidence that backs up each of their conclusions as follows:

  • High-quality evidence. Further research is unlikely to change their conclusion. This is generally reserved for conclusions backed by multiple high-quality studies that have all come to the same conclusion. These are the recommendations that are most often adopted into medical practice.
  • Moderate-quality evidence. This conclusion is very likely to be true, but further research could have an impact on it.
  • Low-quality evidence. Further research is needed and could alter the conclusion. They are not judging whether the conclusion is true or false. They are simply saying more research is needed to reach a definite conclusion.

This is why their reviews are considered the gold standard of evidence-based medicine. If you are of a certain age, you may remember that TV commercial “When EF Hutton talks, people listen.” It is the same with the Cochrane Collaboration. When they talk, health professionals listen.

How Was The Study Done?

Clinical StudyThe authors of this Cochrane Collaboration Report included 61 published clinical trials that randomized participants into two groups.

  • The first group was put on a low carbohydrate diet (carbohydrates = <40% of calories).
  • The second group was put on a “normal carbohydrate” diet (carbohydrates = 45-65% of calories, as recommended by the USDA and most health authorities).
    • The normal carbohydrate diet was matched with the low carbohydrate diet in terms of caloric restriction.
    • Both diets were designed by dietitians and were generally whole food diets.

The participants in these studies:

  • Were middle-aged.
  • Were overweight or obese.
  • Did not have diagnosed heart disease or cancer.
  • May have diagnosed type-2 diabetes. Some studies selected participants that had diagnosed type 2 diabetes. Other studies excluded those patients.

The studies were of 3 types:

  • Short-term: Participants in these studies followed their assigned diets for 3 to <12 months.
  • Long-term: Participants in these studies followed their assigned diets for >12 to 24 months.
  • Short-term with maintenance: Participants in these studies followed their assigned diets for 3 months followed by a 9-month maintenance phase.

What Is The Truth About Low Carb Diets?

The TruthAll the studies included in the Cochrane Collaboration’s meta-analysis randomly assigned overweight participants to a low carbohydrate diet (carbohydrates = <40% of calories) or to a “normal carbohydrate” diet (carbohydrates = 45-65% of calories) with the same degree of caloric restriction.

If low carb diets have any benefit in terms of weight loss, improving blood sugar control, or reducing heart disease risk, these are the kind of studies that are required to validate that claim.

This is what the Cochrane Collaboration’s meta-analysis showed.

When they analyzed studies done with overweight participants without type 2 diabetes:

  • Weight loss was not significantly different between low carb and normal carb diets in short-term studies (3 to <12 months), long-term studies (>12 to 24 months), and short-term studies followed by a 9-month maintenance period.
  • There was also no significant difference in the effect of low carb and normal carb diets on the reduction in diastolic blood pressure and LDL cholesterol.

Since diabetics have trouble controlling blood sugar, you might expect that type 2 diabetics would respond better to low carb diets. However, when they analyzed studies done with overweight participants who had type 2 diabetes:

  • Weight loss was also not significantly different on low carb and normal carb diets.
  • There was no significant difference in the effect of low carb and normal carb diets on the reduction in diastolic blood pressure, LDL cholesterol, and hemoglobin A1c, a measure of blood sugar control.

Of course, the reason Cochrane Collaboration analyses are so valuable is they also analyze the strength of the studies that were included in their analysis.

You may remember in my article two weeks ago, I reported on the Cochrane Collaboration’s report supporting the claim that omega-3 supplementation reduces pre-term births. In that report they said that the studies included in their analysis were high quality. Therefore, they said their report was definitive and no more studies were needed.

This analysis was different. The authors of this Cochrane Collaboration report said that the published studies on this topic were of moderate quality. This means their conclusion is very likely to be true, but further research could have an impact on it.

What Does This Study Mean For You?

confusionIf you are a bit confused by the preceding section, I understand. That was a lot of information to take in. Let me give you the Cliff Notes version.

In short, this Cochrane Collaboration Report concluded:

  • Low carb diets (<40% of calories from carbohydrates) are no better than diets with normal carbohydrate content (45-65% of calories from carbohydrates) with respect to weight loss, reduction in heart disease risk factors, and blood sugar control. Dr. Strangelove has been misleading you again.
  • This finding is equally true for people with and without type 2 diabetes. This calls into question the claim that people with type 2 diabetes will do better on a low carb diet.
  • The published studies on this topic were of moderate quality. This means their conclusion is very likely to be true, but further research could have an impact on it.

If you are thinking this study can’t be true because low carb diets work for you, that is because you are comparing low carb diets to your customary diet, probably the typical American diet.

  • Remember that any whole food diet that eliminates sodas and processed foods and restricts the foods you eat will cause you to lose weight. Whole food keto and vegan diets work equally well short-term compared to the typical American diet.
  • And any diet that allows you to lose weight improves heart health parameters and blood sugar control.

If you are thinking about the blogs, books, and videos you have seen extolling the virtues of low carb diets, remember that the Dr. Strangeloves of the world only select studies comparing low carb diets to the typical American diet to support their claims.

  • The studies included in this Cochrane Collaboration report randomly assigned participants to the low carb and normal carb diets and followed them for 3 to 24 months.
    • Both diets were whole food diets designed by dietitians.
    • Both diets reduced caloric intake to the same extent.

What about the claims that low carb diets are better for your long-term health? There are very few studies on that topic. Here are two:

  • At the 6.4-year mark a recent study reported that the group with the lowest carbohydrate intake had an increased risk of premature death – 32% for overall mortality, 50% for cardiovascular mortality, 51% for cerebrovascular mortality, and 36% for cancer mortality. I will analyze this study in a future issue of “Health Tips From The Professor”.
  • At the 20-year mark a series of studies reported that:
    • Women consuming a meat-based low carb diet for 20 years gained just as much weight and had just as high risk of heart disease and diabetes as women consuming a high carbohydrate, low fat diet.
    • However, women consuming a plant-based low carb diet for 20 years gained less weight and had reduced risk of developing heart disease and diabetes as women consuming a high carbohydrate, low fat diet.

My recommendation is to avoid low-carb diets. They have no short-term benefits when compared to a healthy diet that does not eliminate food groups. And they may be bad for you in the long run. Your best bet is a whole food diet that includes all food groups but eliminates sodas, sweets, and processed foods.

However, if you are committed to a low carb diet, my recommendation is to choose the low-carb version of the Mediterranean diet. It is likely to be healthy long term.

The Bottom Line 

The Cochrane Collaboration, the gold standard of evidence-based medicine, recently issued a report that evaluated the claims made for low carb diets.

All the studies analyzed in the Cochrane Collaboration’s report randomly assigned overweight participants to a low carbohydrate diet (carbohydrates = <40% of calories) or to a “normal carbohydrate” diet (carbohydrates = 45-65% of calories) with the same degree of caloric restriction.

If low carb diets have any benefit in terms of weight loss, improving blood sugar control, or reducing heart disease risk, these are the kind of studies that are required to validate that claim.

The Cochrane Collaboration Report concluded:

  • Low carb diets (<40% of calories from carbohydrates) are no better than diets with normal carbohydrate content (45-65% of calories from carbohydrates) with respect to weight loss, reduction in heart disease risk factors, and blood sugar control.
  • This is equally true for people with and without type 2 diabetes.
  • The published studies on this topic were of moderate quality. This means their conclusion is very likely to be true, but further research could have an impact on it.

My recommendation is to avoid low carb diets. They have no short-term benefits when compared to a healthy diet that does not eliminate food groups. And they may be bad for you in the long run. Your best bet is a whole food diet that includes all food groups but eliminates sodas, sweets, and processed foods.

However, if you are committed to a low carb diet, my recommendation is to choose the low carb version of the Mediterranean diet. It is likely to be healthy long term.

For more details on the study and what it means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Health Tips From The Professor