muscle mass

Protein – The Longevity Nutrient

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How Much Protein Do You Need?

Author: Dr. Stephen Chaney 

breaking newsIn 2016 the New York Times ran an article with the title, “Can You Get Too Much Protein?” The article asserted that most Americans were getting too much protein in their diet and that protein supplements were useless and perhaps dangerous.

At the time I wrote a “Health Tips From the Professor” article summarizing recent research showing that many people needed more than the RDA for protein and that those people were often consuming too little, rather than too much, protein.

In the 9 years since then the evidence that many Americans may not be getting enough protein has only gotten stronger.

  • The standard for protein intake used to be a “one size fits all” recommendation of 46g gm/day for women and 56 gm/day for men with slight increases recommended for pregnant and lactating women. Today we know:
    • That standard was based on outdated methodology from the 1930’s. Recent studies suggest protein intake should be at least 50% higher.
    • That standard was based on studies with healthy, sedentary adults (the adult “couch potato” crowd). Protein requirements are significantly higher for anyone who doesn’t fit that description.
  • We used to think in terms of total daily protein intake. Today we know that:
    • Protein intake should be divided equally between the 3 primary meals.
    • Protein quality is important. Protein requirements should be increased if low-quality proteins are consumed.
  • We used to worry that high protein intake might damage your kidneys. Today we know that:
    • Protein intake does not cause kidney disease. It is not a concern as long as hydration is adequate and excess alcohol is avoided.
    • Protein intake is only a concern if someone has kidney disease.

Protein – Your Longevity Nutrient

If you want to delve into the latest protein research and what it means for you, I highly recommend the book, “Forever Strong: A New, Science-Based Strategy For Aging Well” by Dr. Gabrielle Lyon.

Her book is focused on helping each of us create adequate healthy muscle mass. She says, “Adequate muscle mass is essential for health and longevity. And muscle is the only organ over which we have voluntary and complete control.”

Of course, adequate muscle mass requires both exercise and adequate protein. Dr. Lyon covers both in her book, but exercise is not my expertise, so I will only cover adequate protein intake in this “Health Tips From the Professor” article.

In her book, Dr. Lyons details recent research on the amount of protein needed to optimize muscle mass. Dr. Lyon was the one who alerted me to the fact that the current protein RDA is based on outdated methodology from the 1930’s and that actual protein needs are much higher.

Dr. Lyon concludes that most Americans are not consuming enough protein to optimize their muscle mass and that adequate protein intake is essential for longevity, metabolic function, and quality of life. Specifically, she says that optimal muscle mass:

  • Improves strength and mobility.
  • Improves blood sugar control.
  • Decreases blood triglyceride levels.
  • Strengthens the immune system.
  • Improves bone mineral density and strength.
  • Reduces all-cause mortality (risk of dying) and morbidity (risk of disease).

I will use the latest science on protein needs described in her book and in recently published clinical studies to answer the important question, “How much protein do you need?” But first I want to help you understand the dynamics of protein metabolism.

The Dynamics Of Protein Metabolism 

ProfessorMost people associate muscle mass with strength and endurance. Many understand the important role muscle mass plays in burning off excess calories and keeping us slim. But few people understand the important role that muscle protein plays in our everyday energy metabolism.

Whenever we eat a meal containing protein, we store some of the protein we eat as increased muscle mass, especially when protein intake is coupled with exercise. But muscle protein plays other very important functions. It is a precious resource.

The synthesis of new muscle in the fed state is driven by:

  • Insulin, which is released into the blood stream whenever we eat a meal.
  • Exercise because it makes muscle more sensitive to the effects of insulin.
  • The amino acid leucine, which is most abundant in high quality protein sources.

In the fed state most of our energy is derived from blood glucose. This is primarily controlled by insulin.  As blood glucose levels fall, we move to the fasting state and start to call on our stored energy sources to keep our body functioning. This process is primarily controlled by a hormone called glucagon.

  • In the fasting state most tissues easily switch to using fat as their main energy source, but…
    • Red blood cells and a few other tissues in the body are totally dependent on glucose as an energy source.
    • Our brain is normally dependent on glucose as an energy source, and our brains use a lot of energy. [Note: Our brain can switch to ketones as an energy source with prolonged starvation or prolonged carbohydrate restriction, but that’s another story for another day.]
  • Because our brain and other tissues need glucose in the fasting state, it is important to maintain a constant blood glucose level between meals.
    • Initially, blood glucose levels are maintained by calling on carbohydrate reserves in the liver.
    • But because those reserves are limited, our body starts to break down muscle protein and convert it to glucose as well – even in the normal dinner/sleep/breakfast cycle.

Simply put, in addition to its other important roles in the body, muscle protein is also an energy store. You can think of it like a bank.

When we eat, we make a deposit to that energy store. Between meals we make a withdrawal from that energy store. When we are young the system works perfectly. Unless we fast for prolonged periods of time, we are always adding enough muscle protein in the fed state to balance out the withdrawals between meals.

But there are many physiological situations where protein metabolism becomes unbalanced, either because protein breakdown is accelerated or because protein synthesis is diminished. In each of those situations, our protein needs are increased.

I will describe each of these situations and how they affect our protein needs in the section below.

How Much Protein Do You Need? 

couch potatoThe Coach Potato Group: If this is you, I won’t be judgmental. But I highly recommend you read Dr. Lyon’s book. It may just inspire you to increase your fitness level and your protein intake.

As I said before the standard RDA recommendation for the coach potato group is 46 gm/day for women and 56 gm/day for men. That’s based on 0.36 grams of protein per pound of body weight and assumes that women weigh around 127 pounds and men weigh around 155 pounds.

There are two major problems with the standard protein RDAs:

1) The protein RDA should not be a “one-size-fits-all” recommendation. The standard used to calculate the RDA is based on weight. If you are a woman weighing 127 pounds or a man weighing 155 pounds, you are to be congratulated. But in today’s world the average woman weighs 170 pounds, and the average man weighs 201 pounds.

  • That means the average protein requirement should be 61 gm/day for women and 72 gm/day for men.
  • And that’s just the average. Your protein requirement is based on your weight.

2) As I mentioned earlier, the 0.36 gm/pound standard is based on outdated methodology from the 1930’s. Based on current technology, Dr. Lyon says the standard should be closer to 0.54 gm/pound.

  • If you use that standard and use the current average weight for men and women, the average protein requirement for the couch potato group is closer to 91.5 gm/day for women and 108 gm/day for men.
  • And since protein intake should be divided equally between meals, that amounts to 30 gm/meal for women and 36 gm/meal for men. If you weigh significantly more or less than the average American, you should adjust your intake accordingly.

The Over 50 Group: When we are young muscle protein deposits in the fed state and muscle protein withdrawals during the fasting state are in balance. And if we add exercise and increase our protein intake, it’s pretty easy to increase our muscle mass.

But once we reach our Golden Years things start to change. Muscle protein synthesis becomes less efficient. We need to increase the intensity of our workouts and increase our protein intake just to maintain our muscle mass.

If we fail to do that, we gradually lose muscle mass as we age, a process referred to as sarcopenia. Between 50 and 60 we lose 5-8% of our muscle mass, and the rate that we lose muscle accelerates with each subsequent decade. And that loss of muscle mass has severe consequences. For example:

  • It interferes with daily activities like playing with our grandchildren and engaging in activities we love.
  • It decreases our metabolic rate which increases our risk of obesity and obesity-related diseases.
  • It increases our risk of falls.

In short, our quality of life is diminished, and we become unhealthy and frail.

Dr. Lyon describes the training program needed to prevent sarcopenia as we age in her book Forever Strong. But we also need more protein.

On average older adults need around 35 – 45 gm of protein per meal to prevent sarcopenia. There are not enough published studies for me to provide more specific recommendations. But here are some guidelines:

  • If you are at ideal weight and in your 50’s or 60’s, you can probably do well at the lower end of the range.
  • If you are overweight or in your 70’s or 80’s, you should probably aim for the upper end of the range.
  • I recommend getting a body composition test on an annual basis and adjusting your exercise and protein intake based on your change in muscle mass. My doctor has a simple device for measuring my body composition as part of my annual physical. If your doctor doesn’t have a device like that, find out who does in your community.

Happy woman on scaleThe Weight Loss Group: If you are actively trying to lose excess weight, I congratulate you. But the sad fact is that up to 35% of weight loss on most diets comes from muscle, not fat.

That’s because your body interprets caloric restriction as starvation and increases the rate of protein breakdown.

But you can prevent that by adding resistance training to your diet plan and increasing your protein intake. By increasing your protein intake from 15% of calories (which is what most Americans get) to 30% of calories, you can rebalance muscle metabolism by increasing muscle protein synthesis. When you do this, you can reduce muscle loss to less than 10% of weight loss.

You may be wondering, “Why set the recommendation as a percentage of calories rather than gm/pound or gm/meal”. The answer is simple. Your caloric intake changes significantly you are on a diet, so expressing protein as a percentage of calories makes more sense.

For example, 30% of calories on a 1,000-calorie diet translates into 25-30 gm/meal. You might look at that recommendation and say, “That’s less than you recommended for the couch potato who is not trying to lose weight.” My answer would be, “Yes, but the couch potato is eating 2-3-times more calories.

So, the recommendation that’s easiest to understand if you are trying to lose weight is to aim for 25-30 gm of protein/meal/1,000 calories per day.  

  • Adjust your protein intake per meal based on the daily calories allowed on your diet. 
  • And if you are on a diet that restricts the kinds of food that you can eat or the amount of time you can eat, track your actual caloric intake for a few days. The “hidden secret” behind those diets is that most people eat fewer calories because of the restrictions.

Final thought: The latest data suggest that GLP-1 drugs accelerate the muscle loss associated with dieting. This is a significant concern, especially for people over 50. Some experts are recommending as much as 35-50 gm of protein/meal if you are using a GLP-1 drug to aid your weight loss.

Weight TrainingThe Fitness Group: The question I get most often from the fitness group is, “How much protein do I need after my workout to maximize recovery and muscle gain?” This has been well researched, and the answer is age dependent.

  • If you are in your 30’s, most experts recommend 15-20 grams of protein after your workout.
  • If you are in your 60s, most experts recommend 30-35 grams of protein after your workout.
  • While precise recommendations are not available for every age, you can extrapolate from these numbers.

Does Protein Quality Matter? 

I’m often asked whether all proteins are equally effective at building muscle mass or does protein quality matter? The answer is, “Yes. Protein quality matters, but not in the way that we have thought about it in the past.”

We used to think that protein quality was measured by the balance of all the essential amino acids. While balance is important, the increase in muscle mass is driven primarily by the amino acid leucine. That’s because leucine is the only amino acid that directly stimulates muscle protein synthesis.

Simply put, proteins that are high in leucine are used more efficiently by our bodies to increase muscle mass. In fact, Dr. Lyon measures protein quality solely based on its leucine content.

Many studies have looked at the optimal amount of leucine content in protein. The numbers vary somewhat from study to study, but they average around 1 gram of leucine for every 10 grams of protein.

If you look at the leucine contents of various proteins, it is clear that a 1:10 ratio is primarily found in animal proteins. Soybeans are the only vegetable protein source that comes close.However, there are many health reasons for consuming a primarily plant-based diet. Dr. Lyon doesn’t tell her patients to avoid plant proteins. But if they are consuming primarily plant proteins, she recommends that they increase their protein intake by 35-45%, so they will be getting enough leucine to maximize muscle protein synthesis.

What Role Do Protein Supplements Play? 

Protein SupplementRemember that New York Times article that said protein supplements were useless and perhaps dangerous? That’s outdated advice. In fact, you should view protein supplements as essential for reaching your protein goals.

That’s because our protein intake needs to be divided equally between our 3 major meals, but that’s not how we eat. Most of us have no trouble getting 30-40 grams of protein at dinner, but…

  • We only get around 15 grams of protein at breakfast, and…
  • 15-20 grams of protein at lunch.

But that’s assuming we eat a typical breakfast or lunch. If we eat…

  • An unhealthy breakfast of croissants and coffee or a healthy breakfast of cornflakes, skim milk, and fruit slices, we only get around 6 grams of protein.
  • A healthy green salad for lunch, we may get as little as 2 grams of protein.

A recent study has shown that adding a protein supplement to your low protein meals can help you increase your muscle mass in as little as 24 weeks.

What Does This Mean For You? 

how much protein do athletes needProtein is your longevity nutrient. My advice is:

  • Use the information in this article to set your protein goals (Talk with your doctor first if you have any health issues that may limit your protein intake).
  • Use a simple protein tracker to identify your low-protein meals.
  • Add additional protein foods or supplements to your low-protein meals to bring your protein up to recommended levels.
  • Focus on high-leucine protein foods and supplements. (If you eat more plant protein than animal protein, as I do, increase your recommended protein intake by 35-45% to make sure you are getting the leucine you need to maximize your muscle mass.)

As for what kind of protein supplement, I recommend a plant protein supplement with added leucine.

The Bottom Line 

In her book, “Forever Strong”, Dr. Gabrielle Lyon says, “Adequate muscle mass is essential for health and longevity. And muscle is the only organ over which we have voluntary and complete control.” She goes on to state that the current RDAs for protein intake are outdated. And if we look at protein needs based on the latest research, most Americans aren’t getting enough protein in their diet to achieve adequate muscle mass.

In this article, I summarize her findings. And based on the latest research, I provide protein intake recommendations for:

  • Adult couch potatoes.
  • Fitness enthusiasts.
  • People over 50.
  • People who are trying to lose weight.

I also discuss protein quality and protein supplements.

For more information on these topics and what they mean 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

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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 53 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 Extra Protein Important For Seniors?

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The Role Of Muscle Protein In Energy Metabolism 

Author: Dr. Stephen Chaney 

We’ve been told, “It’s all downhill after 30.” That may or may not be true depending on the lifestyle choices we make.

But for muscle mass, “It’s all downhill after 50!” Simply put, we start to lose muscle mass at an accelerating pace after 50, a process scientists call sarcopenia.

Sarcopenia should be a major concern for everyone over 50. Loss of muscle mass:

  • Causes unsteadiness which can lead to falls, bone fractures, and death.
  • Increases the risk of obesity because muscle burns more calories than fat. That increases our risk of obesity-related diseases such as heart disease, diabetes, some cancers, osteoarthritis, and other inflammatory diseases.
  • Robs us of the fun activities we would like to enjoy in our golden years.

But sarcopenia is not inevitable. As I have discussed in previous issues of “Health Tips From the Professor”, there are three things we can do to minimize sarcopenia as we age.

  • Get adequate weight-bearing exercise. In other words, pump iron or use your body weight for exercise on a regular basis.
  • Get adequate protein.
  • Get adequate amounts of the branched-chain amino acid leucine.

In this article I will focus on the last two, especially the fact that we need more protein and leucine to prevent loss of muscle mass as we age. To help you understand why that is, I am going to share my favorite topic – Metabolism 101 (Once a biochemistry professor, always a biochemistry professor).

Metabolism 101: The Role Of Muscle Protein In Energy Metabolism 

ProfessorMost people associate muscle mass with strength and endurance. Many understand the important role muscle mass plays in burning off excess calories and keeping us slim. But few people understand the important role that muscle protein plays in our everyday energy metabolism.

Let’s start with an overview of metabolism [Note: If you are not interested the details, you can just skip over the bullets and read the take-home message at the bottom of this section.]

  • We get energy from the carbohydrate, fat, and protein we consume. Excess carbohydrate, fat, and protein in our meals are stored to provide the energy our body needs between meals and during prolonged fasting.
    • We have a virtually unlimited ability to store fat, as some of you may have noticed.
    • We have a very limited ability to store carbohydrates in the form of glycogen in our liver.
    • Muscles are our largest organ system, and we can store some of the protein we eat as increased muscle mass, especially when protein intake is coupled with exercise. But muscle protein plays other very important functions. It is a precious resource.
  • In the fed state most of our energy is derived from blood glucose. This is primarily controlled by insulin. As blood glucose levels fall, we move to the fasting state and start to call on our stored energy sources to keep our body functioning. This process is primarily controlled by a hormone called glucagon.
    • In the fasting state most tissues easily switch to using fat as their main energy source, but…
      • Red blood cells and a few other tissues in the body are totally dependent on glucose as an energy source.
      • Initially our brain is totally dependent on glucose as an energy source, and our brains use a lot of energy. [Note: Our brain can switch to ketones as an energy source with prolonged starvation or prolonged carbohydrate restriction, but that’s another story for another day.]
  • Because our brain and other tissues need glucose in the fasting state, it is important to maintain a constant blood glucose level between meals.
    • Initially, blood glucose levels are maintained by calling on the glycogen reserves in the liver.
    • But because these reserves are limited, our body starts to break down muscle protein and convert it to glucose as well – even in the normal dinner/sleep/breakfast cycle.

You may have found the explanation above was excessive, but I couldn’t think of a simpler way of helping you understand that in addition to its other important role in the body, muscle protein is also an energy store.

When we eat, we make a deposit to that energy store. Between meals we withdraw from that energy store. When we are young the system works perfectly. Unless we fast for prolonged periods of time, we are always adding enough muscle protein in the fed state to balance out the withdrawals between meals.

But as we age, our ability to build muscle in the fed state becomes less efficient. Withdrawals exceed deposits, and we experience age-related muscle loss (sarcopenia).

What We Know About Preventing Age-Related Muscle Loss

As I said above, there are three things needed to prevent age-related muscle loss:

  • Adequate resistance exercise.
  • Adequate amounts of protein.
  • Adequate amounts of the essential, branched-chain amino acid called leucine.

And, as I said above, I am going to focus on the last two.

In previous issues of “Health Tips From the Professor” I have shared articles showing that the amount of both protein and leucine needed to maximize the gain in muscle mass following a meal or a workout increase as we age. For example.

  • For someone in their 30s, 15-25 grams of protein with 1.7 grams of leucine per meal is optimal.
  • But someone in their 60’s and 70s needs 25-30 grams of protein and 2.5-2.7 grams of leucine per meal to achieve the same effect.
  • Most of these studies have been done with men, but a recent study showed the results are identical with post-menopausal women.

However, previous studies have not addressed whether we need protein supplementation to achieve adequate protein intake or what kind of protein supplements were best. The studies I will discuss today were designed to answer these questions.

How Were These Studies Done? 

clinical studyStudy #1: As I said above, previous studies have suggested that 25-30 grams of protein per meal is optimal for preventing age-related loss of muscle mass in seniors. However, many seniors get most of their protein in their evening meal. On average, seniors consume

8-15 grams of protein at breakfast, 15-20 grams of protein at lunch, and 30-40 grams of protein at dinner.

This study (C Norton et al, The Journal of Nutrition, 146: 65-67, 2016) was designed to ask whether optimizing protein intake at each meal by adding a protein supplement at breakfast and lunch would increase lean muscle mass in seniors over a 24 week period.

The investigators recruited 60 adults, aged 50-70 (average age = 61) from the city of Limerick, Ireland. The participants were 73% women and had an average BMI of 25.8 (slightly overweight).

The participants were randomly assigned to receive either a milk-based supplement or an isocaloric, non-protein-containing, maltodextrin control. The protein supplement provided 20 grams of protein. The participants were instructed not to change any other aspect of their diet or activity level.

The protein supplement and placebo were provided in identical sachets, and the participants were told to mix them with water and consume them with breakfast and lunch. The protein supplement and placebo looked and tasted identical, so the subjects did not know which group they were in. Compliance was assessed by collecting the used sachets at the end of the study.

The participants completed 4-day diet recalls under the supervision of a dietitian before and during the study. Lean muscle mass was determined prior to and at the end of the 24-week study.

protein shakesStudy #2: This study (J McKendry et al, The American Journal Of Clinical Nutrition, doi: 10.1016/j.ajcnut.2024.05.009) was designed to determine whether the ability to stimulate muscle protein synthesis depended on the type of supplemental protein.

This study was built on the results of the first study. Specifically, the investigators compared the effect on muscle protein synthesis of adding 25 grams of whey, pea, or collagen protein to breakfast and lunch meals.

The investigators enrolled 31 healthy, older (average age = 72) subjects from the Hamilton, Ontario area. Subjects were excluded from the study if:

  • They had a medical condition or were taking any medication that might influence the results.
  • They used tobacco or tobacco related products.
  • They consumed a vegan or vegetarian diet
  • They used a walking device or were inactive for any reason.

The participants were placed on a standardized diet consisting of prepackaged meals (breakfast, lunch, and dinner) and a mix of fruits, vegetables, snacks, and drinks. They were instructed to only eat the foods provided to them and to maintain their normal activity levels.

The diet was designed to provide the RDA for protein (0.8 gram of protein/kilogram of body weight) and to mimic the habitual dietary patterns of seniors in the United States and Canada.

  • Around 55% carbohydrate, 30% fat, and 15% protein.
  • Uneven distribution of protein throughout the day (19% at breakfast, 26% at lunch, and 55% at dinner).

After one week on the control diet, participants were randomly assigned to receive 25-gram protein supplements of either whey, pea, or collagen protein and instructed to add them to their standardized diet for breakfast and lunch (total daily protein intake was increased by 50 grams/day). They followed this regimen for 7 days.

On day one and 7 of the control phase and day 7 of the intervention phase (when the participants were consuming additional protein) muscle biopsies were obtained 90 minutes after breakfast for determination of the effect of the meal on muscle protein synthesis.

[Note: The participants were consuming a protein supplement containing an additional 25 grams of protein at both breakfast and lunch. But the effect of this additional protein on muscle protein synthesis was only determined after the breakfast meal.]

Is Extra Protein Important For Seniors? 

OptimizeEach of the studies provided important insights for anyone wanting to minimize age-related muscle loss.

Study #1: The effect of the 20-gram whey protein supplement for breakfast and lunch as follows:

  • Protein supplementation at breakfast and lunch resulted in a 1.3-pound gain in lean body mass over 24 weeks compared to the control group using an isocaloric, non-protein containing maltodextrin supplement.

The authors concluded, “Protein supplementation at breakfast and lunch for 24 weeks in healthy older adults resulted in a positive (1.3 pound) difference in lean muscle mass compared with an isoenergetic, non-nitrogenous maltodextrin control. These observations suggest that an optimized and balanced distribution of [supplemental] protein intakes could be beneficial in the preservation of lean tissue mass in the elderly.”

Note:

  • This study did not show that these protein levels were optimal. It only showed that using a protein supplement to increase protein intake at breakfast and lunch was beneficial for seniors consuming most of their protein at dinner.

Study #2: The effect of the three 25-gram protein supplements at breakfast and lunch on protein intake was as follows:

  • Adding 25 grams of either whey or pea protein to a relatively low-protein (15 grams) breakfast increased muscle protein synthesis by ~9%.
  • Adding 25 grams of collagen to the same low-protein breakfast had no effect on muscle protein synthesis.

Note: This study did not measure the effect of adding supplemental protein to lunch meal, but the results were probably similar.

The authors concluded, “We discovered that the RDA [for protein] was insufficient to support higher rates of MPS [muscle protein synthesis] in older adults. Manipulating dietary protein to increase daily consumption of higher quality – whey and pea but not collagen – proteins by targeting the lowest protein-containing meals offers a viable strategy to enhance…MPS [muscle protein synthesis] in older adults.”

“Consuming protein much closer to expert group consensus recommendations [1.2 gm/kg instead of the current 0.8 gm/kg for adults over 50] may help to increase…MPS [muscle protein synthesis] with advancing age and extend health-span – compressing the years of disease and disability commonly experienced by older individuals closer to the end of life.”

My comments are:

  • You may recall from the previous discussion that age-related muscle loss occurs because muscle protein synthesis (MPS) becomes less efficient as we age.
    • Therefore, an increase in muscle protein synthesis following each meal will lead to an increase in muscle mass over time, as was seen in the first study.
  • In our 60’s and beyond we require higher amounts of both protein and leucine to maximize muscle protein synthesis.
    • The collagen supplement used in this study provided enough supplemental protein. But it probably was ineffective because it only provided 0.86 grams of leucine.
      • The amount of leucine in the control diet was not specified, but with only 15 grams of protein for breakfast there was probably enough leucine to make up for the lack of leucine in the collagen supplement.
    • In contrast the whey and pea supplements provided 2.7 and 2.1 grams of leucine, respectively. When added to the leucine in the control diet, this would be more than enough to drive muscle protein synthesis.
  • Not every pea protein supplement may be as effective as the one used in this study. When I looked it up, it was described as an “enriched pea protein designed as a soy and milk alternative.” The manufacturer did not say how it was “enriched”, but I suspect it was enriched by adding extra leucine.

What Do These Studies Mean For You? 

Don’t Leave Out Resistant Exercise. These studies were focused on the timing and quality of protein. But don’t forget that adequate protein and leucine are only two of the requirements for preventing age-related muscle loss. The third, and arguably the most important, is resistance exercise.

Aim for at least three 30-minute resistance exercise sessions per week. If you have physical limitations consult with your health professional about the type, duration, and intensity of resistance exercise that is right for you.

Forget What You Have Been Told About Protein. You have been told that American consume too much protein. That’s probably true for the average couch potato. But it is not true for seniors. The average American does consume too much of the wrong kind of protein, but that’s another story for another day.

You have been told that the average woman only needs 46 grams of protein per day, and the average man needs only 56 grams of protein per day. That’s based on the RDA of 0.8 gm/kg (0.36 gm/pound) and an average weight of 127 pounds for women and 155 pounds for men.

We haven’t weighed that since the 50’s. Today the average woman weighs 170 pounds, and the average man weighs 201 pounds. That means protein intake should be at least 61 gm/day for women and 72 gm/day for men.

But that’s only if you are in your twenties or thirties. The consensus among those who study protein needs in seniors is that the RDA should be 1.2 gm/kg (0.54 gm/pound) for adults over 50. That’s 91 gram/day and 108 grams/day, respectively, for average weight women and men.

With that perspective, it is easy to understand the recommendation that seniors get 25-30 grams of protein and 2.5-2.7 grams of leucine per meal.

These studies did not address leucine intake, but they suggest that optimal protein intake may be closer to 30-40 grams of protein per meal. That’s 90-120 grams of protein day. But that is probably not what you are hearing from your doctor.

Why Is Supplemental Protein Important? It’s easy to say that seniors should get 30-40 grams of protein per meal, but that’s not the way most seniors eat.

When I was a child growing up in Alabama the standard breakfast was eggs, ham, grits with ham gravy and biscuits. I’m not saying that it was a healthy breakfast, but it was the standard breakfast where I lived at the time. And it provided plenty of protein.

In today’s world most seniors have been told to avoid eggs and red meat. Breakfasts are more likely to be some type of cereal with a fruit garnish and perhaps some toast. That’s a much healthier breakfast, but it’s a low-protein breakfast. That’s why most seniors only get 8-15 grams of protein at breakfast time.

I won’t go into lunches, but similar transformations have taken place at lunch time, which is why most seniors only get 15-20 grams of protein at lunch.

CerealAnd many seniors get even less protein at breakfast and lunch. For example:A cup of coffee and a croissant or a “healthier” bowl of cornflakes and skim milk at breakfast only provides 6 grams of protein.

  • A healthy green salad at lunch only provides 2 grams of protein.

In cases like this, the protein supplements may need to provide 30-40 grams of protein rather than the 20-25 grams of protein used in these studies.

So, if you want to avoid age-related muscle loss you have two choices:

  • Completely change your diet and incorporate more healthy protein foods into your breakfast and lunch menus or…
  • Add a protein supplement to your low-protein meals. The studies I have described above suggest that 20-25 grams of supplemental protein may be sufficient to transform a low-protein meal into one that will support muscle protein synthesis and minimize age-related muscle loss.
  • And if your breakfast and lunches are very low in protein, 30-40 grams of supplemental protein may be necessary to optimize protein intake.

Why Is Protein Quality Important? The second study shows that having enough protein is not sufficient to stimulate muscle protein synthesis. It must be high quality protein.

The authors of the study suggested that collagen did not stimulate muscle protein synthesis due to its low leucine content.

And, as I mentioned earlier, the pea protein used in the study was “enriched” so it could be used as a “whey or soy alternate”, and the “enrichment” probably included adding extra leucine.

So, if you are planning to use a plant protein supplement with your low-protein meal(s), I would recommend choosing one with added leucine.

How Much Protein Is Too Much? That depends on your age. If you are in your 20s or 30s, the ability of a protein meal and/or supplement to stimulate muscle protein synthesis begins to plateau at around 30 grams of protein, so there is little advantage to protein intakes above 30 grams at one time.

But if you are a senior, you use protein less efficiently. These and other studies with seniors suggest that 30-40 grams of protein per meal may be optimal.

However, high protein intake can be risky for some. The risk is smaller than you have been told, but it is not zero. Here are my recommendations:

  • If your physician has told you to limit protein intake, follow their advice.
  • If you are unsure about the health of your kidneys, consult with your physician before increasing your protein intake.
  • Keep adequately hydrated. Byproducts of protein metabolism can stress your kidneys if you are dehydrated.

What About An After-Workout Supplement? Previous studies have shown that the numbers are about the same for after-workout supplements.

  • For someone in their 30s, 15-25 grams of protein with 1.7 grams of leucine per meal is enough to maximize muscle gain after a workout.
  • But someone in their 60s or 70s needs at least 25-30 grams of protein and 2.5-2.7 grams of leucine per meal to maximize muscle gain.

One Final Pearl

At the very beginning of this article, I told you that the breakdown of muscle protein to keep blood sugar levels constant during fasting and starvation was driven by a hormone called glucagon.

And the active ingredient in the latest weight loss drugs like Wegovy, Ozempic, and Trulicity is GLP-1, which stands for glucagon-like peptide 1.

So, it should be no surprise that those drugs cause loss of muscle mass. That’s a side effect you probably haven’t been told about.

But the good news is that properly designed protein supplements can help you maintain and (with resistance training) increase muscle mass and also boost GLP-1 levels naturally. When choosing your protein supplement, ask for clinical studies showing that they increase GLP-1 levels.

The Bottom Line 

It’s all downhill after age 50! That’s when we start to experience age-related muscle loss, something called sarcopenia.

Age-related muscle loss can be prevented with resistance exercise, adequate protein, and adequate leucine. And the amount of both protein and leucine we need to prevent muscle loss increases as we age.

Previous studies have defined the amount of protein and leucine we need to prevent muscle loss in our 60s and 70s. The studies described in today’s “Health Tip” show the benefit of adding a protein supplement to our low-protein meals and the importance of a high-quality protein supplement for minimizing age-related muscle loss.

The authors of one of these studies concluded, “Consuming protein much closer to the expert group consensus recommendations [1.2 gm/kg instead of the current 0.8 gm/kg for adults over 50] may help to increase…MPS [muscle protein synthesis] with advancing age and extend health-span – compressing the years of disease and disability commonly experienced by older individuals closer to the end of life.”

For more information on these studies, how much protein you need, and what they mean 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.

 

 

600th Issue Celebration

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Nutrition Advances Over The Last Two Years

Author: Dr. Stephen Chaney 

celebrationIn the nearly twelve years that I have been publishing “Health Tips From The Professor”, I have tried to go behind the headlines to provide you with accurate, unbiased health information that you can trust and apply to your everyday life.

The 600th issue of any publication is a major cause for celebration and reflection – and “Health Tips From The Professor” is no different.

I am dedicating this issue to reviewing some of the major stories I have covered in the past 100 issues. There are lots of topics I could have covered, but I have chosen to focus on three types of articles:

  • Articles that have debunked long-standing myths about nutrition and health.
  • Articles that have corrected some of the misinformation that seems to show up on the internet on an almost daily basis.
  • Articles about the issues that most directly affect your health.

Here are my picks from the last two years:

Weight Loss Diets

weight lossSince it is almost January, let’s start with a couple of articles about diet and weight loss (or weight gain). I have covered the effectiveness of the Paleo, Keto, Mediterranean, DASH, vegetarian, and Vegan diets for both short and long-term weight loss in my book “Slaying The Food Myths”, so I won’t repeat that information here. Instead, I will share a few updates from the past 100 issues.

Is Time-Restricted Eating Better Than Other Diets? Time-restricted eating is one of the latest fads. But is it really better than other diets for weight loss and improved health? In this article I reviewed two studies that compare time-restricted eating with diets that do not restrict time of eating but cut calories to the same extent. You may be surprised at the results.

Can You Lose Weight Without Dieting? In this article I share 8 tips for losing weight without going on a diet. The article is based on research by Dr. Brian Wansink, a behavioral psychologist who specializes in studying how external clues influence our eating patterns. As you might suspect his 8 tips for losing weight have nothing to do with counting calories or going on restrictive diets.

Healthy Diets

dairy foodsIs Whole Fat Dairy Healthy? For years dietary guidelines have been telling us to select low fat dairy foods. But some health gurus are telling you that isn’t true. They claim whole fat dairy is healthy. So, you are probably wondering, “What is the scoop (as in ice cream) on whole fat dairy?” In this article I look at the study behind the headlines and answer that question. But the answer is not a simple “Yes” or “No”. The answer is more nuanced. It turns out that whole fat dairy is healthier in some diets than in others. 

Are Low Carb Diets Healthy? Are low carb diets good for you or bad for you? It depends on which study you quote. Two major studies in recent years have come to opposite conclusions. In this article I help you sort through the conflicting studies and rephrase the question. Instead of, “Are low carb diets healthy”, the question should be, “Which low carb diets are healthy?”

Are All Plant-Based Diets Healthy? Plant-based diets have acquired a “health halo” in recent years. Your mama told you to eat your fruits and vegetables. And many health gurus have been telling you not to neglect your grains, legumes, nuts, and seeds as well. But some of these foods require a lot of food preparation.

Never fear! The food industry has come to your rescue with a wide variety of processed plant-based foods. No need for food prep. But are they as good for you as the unprocessed plant foods they replace? In this article I review a study that answers that question.

You probably know what that answer is, but the article is worth a read anyway. That is because the study also asks whether vegan and vegetarian diets are healthier than other primarily plant-based diets. And you may not know the answer to that question.

Diet And Heart Disease

egg confusionAre Eggs Bad For You? For years we were told that eggs are bad for us because they contain cholesterol. Then we were told that eggs in moderation may not increase our risk of heart disease. And recently studies have appeared claiming eggs may be good for our hearts. What is the truth about eggs and heart disease? In this article I review a recent study claiming eggs are bad for our heart and put that study into the context of other recent studies to clear up the “eggfusion”.

Which Diets Are Heart Healthy? Every popular diet claims to help you lose weight, reduce your risk of diabetes, and reduce your risk of heart disease. All these claims can’t be true. Which diets deliver on their promises, and which are just pretenders? In this article I review a recent study that answered that question for heart disease.

This study was a very large metanalysis of over 40 studies with 35,548 participants that looked at the effect of different diets on heart disease outcomes. The study identified two diets that significantly reduced the risk of heart disease. There are other diets that might reduce the risk of heart disease, but their benefits have not been proven by high quality clinical studies. They are merely pretenders.

The Dangers Of Processed Foods 

In previous issues of “Health Tips From the Professor” I have shared articles showing that diets high in processed foods are associated with an increased risk of obesity, diabetes, and heart disease. But the story keeps getting worse. Here are two articles on recent studies about processed foods that appeared in “Health Tips From The Professor” in the last two years.

Why Does Processed Food Make You Fat? We already know that eating a lot of highly processed food is likely to make us fat. But what is it about processed food that makes us fat? In this article I review a recent study that answers that question.

This study is interesting for two reasons.

  • It identifies the characteristics of processed foods that make us want to eat more.
  • It identifies some minimally processed foods that have the same characteristics and suggests we should choose minimally processed foods wisely. Simply put, knowledge is power. We may want to avoid minimally processed foods that have the same obesity-inducing characteristics as processed foods.

Do Processed Foods Cause Cancer? Previous studies have shown that processed food consumption is associated with a higher risk of obesity, diabetes, and heart disease. Can it get any worse? In this article I review a recent study that shows processed food consumption is associated with an increased risk of several kinds of cancer.

Maintaining Muscle Mass As We Age

As we age, we begin to lose muscle mass, a process called sarcopenia. Unless we actively resist loss of muscle mass it will eventually impact our quality of life and our health.

We can prevent this loss of muscle mass with resistance exercise, adequate protein intake, and adequate intake of the amino acid leucine. Previous studies have shown people over 50 need more of each of these to maintain muscle mass, but the amount they need has been uncertain until now. Three recent studies have given seniors better guidelines for maintaining muscle mass.

Can You Build Muscle In Your 80s? In this article I review a recent study that enrolled a group of octogenarians in a high-intensity exercise program to see if they could gain muscle mass. They were able to increase their muscle mass, but the intensity of the exercise required may surprise you.

Optimizing Protein Intake For Seniors. In this article I review two recent studies that looked at the amount, timing, and kind of protein needed for seniors in their 60s and 70s to maximize gain in muscle mass.

How Much Leucine Do Seniors Need? In this article I review a recent study that determined the amount of leucine seniors in their 70s need to optimize gains in muscle mass and strength.

The Benefits And Risks Of Supplementation

Omega-3s And Heart DiseaseIf you listen to Big Pharma or the medical profession, you hear a lot about the “risks” of supplementation and very little about the benefits. In “Health Tips From the Professor” I try to present a more balanced view of supplementation by sharing high-quality studies showing benefit from supplementation and studies that put the supposed risks into perspective.

The Good News About Omega-3s and Stroke. Multiple studies have shown that omega-3 supplementation reduces the risk of ischemic strokes (strokes caused by a blood clot). But it has been widely assumed they might increase the risk of hemorrhagic strokes (strokes caused by bleeding). In this article I review a meta-analysis of 29 clinical studies with 183,000 participants that tested that assumption.

How Much Omega-3s Are Best For Blood Pressure? Multiple studies have shown that omega-3 supplementation can reduce high blood pressure. But the doses used vary widely from one study to the next. In this article I review a meta-analysis of 71 double-blind, placebo-controlled clinical studies that determined the optimal dose of omega-3s for controlling blood pressure.

Omega-3 Supplements Are Safe. As I said above, it has been widely assumed that omega-3 supplementation increases the risk of bleeding and hemorrhagic stroke. In this article I review the definitive study on this topic. More importantly, it reveals which omega-3 supplements might increase bleeding risk and which do not.

Are Calcium Supplements Safe? Big Pharma and the medical profession have been warning us that calcium supplements may increase heart disease risk. In this article I review the definitive study on this topic.

Prenatal Supplements

prenatal dha supplementIf you are pregnant or thinking of becoming pregnant, your health professional has likely recommended a prenatal supplement. You probably assume that prenatal supplements provide everything you need for a healthy pregnancy. Unfortunately, recent research has shown that assumption is not correct.

Is Your Prenatal Supplement Adequate? In this article I review a study that should serve as a wakeup call for every expectant mother. It showed that most prenatal supplements were woefully inadequate for a healthy pregnancy.

What Nutrients Are Missing In Prenatal Supplements? In this article I review a study that identified additional nutrients that are missing in most prenatal supplements.

Prenatal Supplements Strike Out Again. In this article I review a study that looked at the diet of pregnant women to determine their needs and compared that to the nutrients found in prenatal supplements. Once again, most prenatal supplements were woefully inadequate. Is it, “Three strikes and you are out”?

Exercise

Walking FastWalking Your Way To Health. We have been told that walking is good for our health. But how many steps should you take, how fast should you walk, and does it matter whether these steps are part of your daily routine or on long hikes? In this article I review a study that answers all these questions.

Which Exercise Is Best For Reducing Blood Pressure? If you have high blood pressure, you have probably been told to exercise more. But which exercise is best? In this article I review a study that answers that question. And the answer may surprise you.

Did You Know? 

Question MarkIf you have been reading “Health Tips From the Professor” for a while, you probably know that I enjoy poking holes in popular myths. Here are two new ones I deflated in past two years.

Is Low Alcohol Consumption Healthy? You have probably heard that low alcohol intake (that proverbial glass of red wine) is good for you. But is that true? In this article I review a recent study that shows that myth was based on faulty interpretation of the data and provides a more nuanced interpretation of the data.

Is HDL Good For Your Heart? You have been told that increasing your HDL levels reduces your risk of heart disease so many times it must be true. But is it? In this article I review HDL metabolism and a recent study to provide a more nuanced interpretation of the relationship between HDL and heart disease risk.

How To Talk With Your Doctor About Cancer 

Because of my years in cancer research, I am often asked whether someone should follow their oncologist’s advice and go on a recommended chemotherapy or radiation regimen. Of course, it would be unethical for me to provide that kind of advice.

In this article I tell you the questions to ask your oncologist about the prescribed treatment regimen, so you can make an informed decision. However, I also recommend you only ask these questions if you can handle the answers.

The Bottom Line

I have just touched on a few of my most popular articles above. You may want to scroll through these articles to find ones of interest to you that you might have missed over the last two years. If you don’t see topics that you are looking for, just go to https://chaneyhealth.com/healthtips/ and type the appropriate term in the search box.

In the coming years, you can look for more articles debunking myths, exposing lies and providing balance to the debate about the health topics that affect you directly. As always, I pledge to provide you with scientifically accurate, balanced information that you can trust. I will continue to do my best to present this information in a clear and concise manner so that you can understand it and apply it to your life.

Final Comment: You may wish to share the valuable resources in this article with others. If you do, then copy the link at the top and bottom of this page into your email. If you just forward this email and the recipient unsubscribes, it will unsubscribe you as well.

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/lifestylechange/.

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.

How Much Protein Do Post-Menopausal Women Need?

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Does The Design Of The Protein Supplement Matter? 

Author: Dr. Stephen Chaney 

Frail ElderlyYou’ve probably heard the saying, “It’s all downhill after 30”. That’s a particularly gloomy way of looking at it, but Father Time does take a toll on our body. I’m going to focus on age-related loss of muscle mass today, a physiological process called sarcopenia.

There are three factors that influence the rate at which we lose muscle mass as we age:

1) Our physiology changes. Our bodies break down our protein stores more rapidly and we have a harder time utilizing the protein in our diet to replenish those protein stores.

2) We become less active. In some cases, this reflects physical disabilities, but all too often it is because we are not giving weight-bearing exercises the proper priority in our busy lives.

3) Our diets become inadequate. The major driver of this phenomenon is loss of appetite which results in decreased caloric intake. However, physical disability, isolation, and insufficient income also contribute.

Sarcopenia in turn results in:

  • Loss of muscle strength. Even the simple act of picking up a grandchild or a bag of groceries can become problematic.
  • Increased risk of falls and fractures.
  • Lower quality of life.

Obviously, sarcopenia is a major health issue for those of us in our golden years. If you are younger, it is a concern for your parents or grandparents. Sarcopenia is a health issue that affects everyone.

But what can be done to prevent sarcopenia? We can’t change our physiology, but we can change our activity level and our diet. Weight-bearing exercise tugs on our muscle fibers. That stimulates those fibers to incorporate protein into new muscle cells. It is no wonder that weight-bearing exercise is recommended for preventing sarcopenia.

What about diet? Are older adults getting enough protein in their diet to benefit from weight-bearing exercise? I have shared studies showing that older adults need more protein and higher levels of the amino acid leucine to benefit from their workouts.

But those studies were done with men. There have been no studies comparing younger and older women until now.

In this article, I discuss a recent study (CF McKenna et al, Journal of Applied Physiology, Feb 22, 2024 doi.org/10.1152/applphysiol.00886.2023) that asks how much protein is needed to stimulate muscle protein synthesis following a workout in post-menopausal women and compares it to the protein needs of younger women.

How Was The Study Done? 

clinical studyThe investigators enrolled 16 post-menopausal women who were part of a much larger study investigating exercise and nutritional regimens that preserve and/or enhance muscle mass in women.

The women in this study were on average 60 years old with a BMI of 26 (overweight). They had no heart disease, dietary restrictions, and did not take any supplements that could affect protein metabolism.

They were compared to a cohort of pre-menopausal women (average age = 24, BMI = 25 (borderline overweight)) recruited from the same large study. The experimental protocol was the same for the pre-menopausal and post-menopausal cohorts.

The study design was what is called a parallel-group design. Simply put, one leg was exercised using a leg extension machine, while the other leg was rested. The rested leg served as the control for each participant in the study.

Participants were tested ahead of time to determine the “one-repetition maximum” (1RM) weight for complete leg extension for each participant.

On the day of the experiment participants arrived in the laboratory after an overnight fast. One iv line was inserted, and a labeled amino acid was infused into the bloodstream, so the investigators could measure new protein synthesis at any time during the 4-hour experiment. Another iv line was inserted, so the investigators could withdraw blood samples.

At the beginning of the experiment, each participant was given either a whey protein drink (whey protein isolate fortified with vitamins C, B1, B2, B3, folate, B6, and B12 and minerals calcium, magnesium, iron, zinc, and potassium) or water. They then performed a bout of single-leg extensions starting with a warm-up of 2 sets of repetitions at 30% 1RM followed by 3 sets of 12 repetitions at 65% 1RM with 90 seconds of rest provided between sets.

Immediately following exercise, muscle biopsies were collected from both legs (t=0). Muscles biopsies were also collected at 120 and 240 minutes after exercise. Blood samples were collected continually during the experiment.

Muscle tissue was isolated from each biopsy, and something called myofibrillar protein synthesis (protein synthesis in muscle fibers) was determined based on the amount of labeled amino acid incorporated into muscle protein. The amount of protein synthesis due to exercise was determined by subtracting the incorporation of labeled amino acid in muscle fibers in the rested leg from that in the exercised leg.

What Is Leucine? 

leucine protein and exerciseLeucine is an essential amino acid. It is present in all dietary proteins, but it is more abundant in whey and soy protein than in some vegetable proteins.

Leucine is also one of three branched-chain amino acids (valine and isoleucine are the other two). If you are familiar with the weightlifting and body-building world, you will know that branched-chain amino acids are thought to be important for muscle gain. However:

  • It turns out that leucine is the only branched chain amino acid that stimulates muscle protein synthesis (Am J Physiol Endocrinol Metab 291: E381-E387, 2006). And protein is what gives muscles their strength and their bulk.
  • The other branched chain amino acids appear to play a supporting role in the quantities that occur naturally in most proteins. And adding extra valine and isoleucine to a protein supplement appears to reduce the effectiveness of leucine at stimulating muscle gain (Am J Physiol Endocrinol Metab 291: E381-E387, 2006).

What Have Previous Studies Shown? 

weight lifting exerciseWith respect the amount of protein needed to optimize muscle gain after workouts, previous studies have shown that: 

  • The optimal protein intake for maximizing muscle gain post workout is 15-20 gm for young men (Katsanos et al, Am J Clin Nutr 82: 1065-1073, 2005; Moore et al, Am J Clin Nutr, 89: 161-168, 2009) and 20-25 gm for older men (Symons et al, Am J Clin Nutr 86: 451-456, 2007).
  • More protein isn’t necessarily better. The effect of protein intake on post workout muscle gain maxes out at around 25 gm for young men and 30 gm for older men (Symons et al, J Am Diet Assoc 109: 1582-1586, 2009).
  • Whey protein is the best choice for enhancing muscle gain immediately after a workout. Other protein sources (soy, casein, chicken) are better choices for sustaining muscle gain over the next few hours.
  • A previous study by the authors of the present study showed that 15 gm of whey protein was sufficient to stimulate muscle protein synthesis in young women (average age 20). Thus, young women and young men both appear to benefit from 15 gm of protein after a workout.

How Much Protein Do Post-Menopausal Women Need? 

This is a complex study, so let’s just start with the big takeaway from the study:

  • The same whey protein supplement that increased muscle mass in younger women failed to stimulate “cumulative muscle protein synthesis” [net increase in muscle mass] in post-menopausal women. (This was measured by determining net accumulation of labeled amino acids into the muscle fibers of the exercised leg compared to the rested leg.)

With that out of the way, we can focus on some less important findings:

  • There was a short-term (0-2h) transient increase in muscle protein synthesis following exercise with and without the whey protein supplement, but the result was not cumulative. In other words, the transient protein synthesis did not result in an increase in muscle mass.
  • There was a long-term (2-4h) transient increase in muscle protein synthesis following exercise for the group taking the whey protein supplement, but, again, the result was not cumulative. It did not result in a net increase in muscle mass.
  • In the group taking the whey protein supplement there was a transient increase in both insulin and leucine in the blood between 2 and 4 hours. Either or both could have driven the transient increase in protein synthesis observed during that same times.

In the words of the authors, “Ingestion of 15 gm whey protein failed to stimulate [net] myofibrillar (muscle) protein synthesis in post-menopausal women. While resistance exercise with and without feeding stimulate late (2-4 h) and early (0-2h) increases in myofibrillar protein synthesis, further exercise and nutritional manipulations may be necessary to robustly stimulate the skeletal muscle adaptive response to exercise.”

They went on to say that increased exercise intensity and/or increased protein intake may be necessary for post-menopausal women to maintain or increase muscle mass.

What Does This Study Mean For Post-Menopausal Women? 

Questioning WomanI should start by acknowledging that this was a small study, as are most studies in this field of research. In part this reflects the expense of these experiments and the lack of major government support. But it also reflects the difficulty in recruiting subjects for this kind of experiment. They are hooked up to two iv’s for over four hours and have three muscle biopsies removed from each leg during that time. That’s a pretty invasive experimental protocol.

With this limitation in mind, the biggest takeaway from this study is that post-menopausal women need more protein to build muscle mass than younger women. Young women, just like young men, can build muscle mass with as little as 15 gm of protein post-workout.

Unfortunately, this study did not determine how much protein post-menopausal women need to build muscle mass post-workout. And that is a critical question, because women typically have less muscle mass than men when sarcopenia starts to set in. Resistance (weight-bearing) exercise and adequate protein intake are key to preventing the debilitating effects of sarcopenia in post-menopausal women.

In their conclusion, the authors said that “…further exercise and nutritional manipulations may be necessary [to optimize the post-workout gain in muscle mass for post-menopausal women].”

From an exercise standpoint, the authors speculated that higher intensity exercise may be needed to increase muscle mass in post-menopausal women. However, the exercise protocol they used was based on public health recommendations for resistance training for older adults. A more rigorous exercise protocol might not be suitable for many post-menopausal women.

From a nutritional standpoint, they noted that a previous study had shown that 35 gm of protein post-workout was sufficient to build muscle mass in post-menopausal women. However, they considered 35 gm of protein to be a dangerously high intake for a single serving of protein for post-menopausal women. I concur.

In summary, we know that 15 gm of protein post-workout is too little for postmenopausal women, and while 35 gm of protein is sufficient, it is probably too much. Until further studies are performed in post-menopausal women, I would recommend the 20-25 gm of protein shown to support post-workout muscle gain in older men.

But it is not just the amount of protein that is important. The design of the protein supplement also matters.

Does The Design Of The Protein Supplement Matter? 

Protein SupplementWhile the amount of protein in a post-workout supplement is important, the design of the protein supplement also matters. While there are lots of crazy claims on the internet, there are two natural ways to maximize the effect of a protein supplement on muscle mass. Insulin and the amino acid leucine both drive muscle protein synthesis and help maximize post-workout muscle gain.

  • Recent research has shown that 2-3 gm of leucine (2 gm for young men; 3 gm for older men) is sufficient to maximize post workout muscle gain if protein levels are adequate (Am J Physiol Endocrinol Metab 291: E381-E387, 2006). We don’t know the corresponding leucine requirements for women, so we will need to assume they are similar.
    • A 15-gram serving of whey protein isolate only provides 1.4 gm of leucine, far below what is likely to be needed to drive post-workout muscle gain in post-menopausal women.
    • If you are a man over 50 or a post-menopausal woman, you should look for a post-workout protein supplement containing added leucine. And even younger adults will get “more bang for your buck” by choosing protein supplements with added leucine.
  • The insulin response is maximized when the carbohydrate to protein ratio is around 2.5 to 1. The manuscript did not list carbohydrates among the ingredients used in the whey protein supplement used in this study. But if it is like many whey protein supplements nowadays, it probably contained little or no carbohydrate.
    • Although less popular in today’s low carbohydrate world, post-workout supplements with a high carbohydrate to protein ratio are also effective in maximizing post-workout muscle gain.

The Bottom Line 

Sarcopenia (age-related muscle loss) is a major concern for older Americans. Sarcopenia can result in:

  • Loss of muscle strength. Even the simple act of picking up a grandchild or a bag of groceries can become problematic.
  • Increased risk of falls and fractures.
  • Lower quality of life.

Sarcopenia can be prevented by a combination of resistance exercise and adequate amounts of protein following the workout.

We know that older men require more protein than young men in a post-workout supplement designed to help them maximize the muscle gain associated with resistance exercise. But similar experiments had not been performed with women until now.

In the article above I share a study that shows that post-menopausal women need more protein than young women in a post-workout supplement. But the study did not determine how much protein they need.

I also discuss the amount of protein post-menopausal women likely need in a post-workout supplement, and how that protein supplement could be designed to maximize muscle gain and prevent sarcopenia.

For more information on this study and my recommendations 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

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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.

Does Time-Restricted Eating Have A Downside?

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Are The Benefits Of Time-Restricted Eating An Illusion?

 Author: Dr. Stephen Chaney

intermittent fastingWeight loss is difficult. If you are like most American adults, you have tried at least 5 or 6 diets by the time you are 50, and all of them have failed. Or maybe you have found a diet that works reasonably well at helping you lose weight, but it’s difficult to stick with. And you worry that it may not be healthy long-term.

But hope springs eternal, and there are always new diets to try. One of the newer diet fads is something called intermittent fasting. The most popular form of intermittent fasting (because it is the easiest to follow) is something called time-restricted eating.

The concept is simple. You don’t change what you are eating. Instead, you restrict the time during which you are eating those foods. Typically, you restrict your time of eating to 8 hours a day and abstain from all food the rest of the day. Hence, the term “time-restricted eating”.

I won’t go into the supposed benefits of time-restricted eating. You have probably heard those already from advocates of this form of eating. But you may be wondering if those benefits are true and whether time-restricted eating has any drawbacks.

Fortunately, a recent study (T Moro et al, Medicine and Science In Sports & Exercise, 53, 2577-2585, 2021) answers those questions. It put a group of athletes on either a control diet or a time-restricted diet for an entire year and looked at the relative benefits and drawbacks of both diets.

How Was This Study Done?

Clinical StudyThis study recruited 19 healthy, resistance-trained males (average age = 29, average weight = 185 pounds) for the study. All the subjects had at least 5 continuous years of resistance training, no steroid use, and no known medical conditions.

The subjects completed a 7-day food diary prior to the study, at the end of 2 months, and at the end of 12 months. The participants were instructed not to change their usual caloric intake or diet composition. In addition, each participant received a personalized diet protocol based on the analysis of their food diary at baseline.

The results from the first two months have previously been reported (T Moro et al, Journal of Translational Research, 14: 290, 2016). This report covers the subsequent 10 months.

During the first two months, the participants were contacted weekly by a dietitian to ensure adherence to the diet. During the interviews, the dietitian asked questions about meal timing and composition, appetite, and any difficulties in maintaining the diet protocol. When necessary, the dietitian gave advice to improve adherence to the diet. During the subsequent 10 months, the participants were contacted less frequently, and the interviews were shorter.

The participants were divided into two groups. The selection was random except that the two groups were matched with respect to caloric intake at baseline (~2,900 calories/day).

The ND (normal meal distribution) group ate their meals over a 12-hour period, with meals at ~8AM, 1 PM, and 8 PM. The distribution of calories for this group was 25%, 40%, and 35% over the three meals.

The TRE (time-restricted eating) group ate their meals over an 8-hour period, with meals at ~1PM, 4 PM, and 8 PM. The distribution of calories for this group was 40%, 25%, and 35% over the three meals.

The training regimen consisted of strength training specifically designed to increase muscle mass. A standardized 3-times per week training regimen was established during the first two months of supervised training. The participants continued the same training regimen on their own for the next 10 months. Workouts were performed between 4 and 6 PM to fall within the eating window for both groups.

Finally, tests for inflammatory markers, cholesterol & other blood lipids, blood sugar control, hormones, body composition, and strength were performed before the program started, at 2 months, and again at 12 months.

What Are The Benefits Of Time Restricted Eating?

thumbs upWhen the investigators looked at health outcomes at the end of 12 months:

  • Inflammatory markers were significantly reduced in the TRE (time-restricted eating) group compared to the ND (normal meal distribution) group.
  • Blood sugar control was significantly improved in the TRE group compared to the ND group.
  • Lipid profiles were significantly improved in the TRE group compared to the ND group.

These results are consistent with the findings of earlier short-term studies on the benefits of time restricted eating.

The authors concluded. “Our results suggest that long-term time-restricted eating in combination with a resistance training program is feasible, safe, and effective in reducing inflammatory markers and risk factors.”

At this point you are probably thinking, “It sounds like everything I have heard about time-restricted eating is true. I can’t wait to get started.”

What Causes The Benefits Of Time-Restricted Eating?

SkepticBefore you jump on the time restricted eating bandwagon, let’s look more closely and ask what caused these apparent health benefits.

When the investigators looked at changes in caloric intake over the 12-month period:

  • The TRE group spontaneously decreased their total caloric intake by 6.4% in spite of being told not to change their diet.
    • The decrease in caloric intake was driven by a decrease in both carbohydrate and fat intake, while protein intake remained constant.
    • Most of this change occurred between 2 and 12 months when they were no longer being closely supervised by dietitians.
  • In contrast, caloric intake and macronutrient intake did not change significantly for the ND group.

The reason for the decrease in caloric intake is not known.

  • If you follow social media or blogs about time-restricted eating, you have been given some scientific-sounding mumbo-jumbo about how the 16 hours of fasting changes your metabolism and/or reduces your appetite. However, this is speculation. There is scant evidence for it.
  • A more likely explanation is that when you restrict the time you allow yourself to eat, you naturally eat less without thinking about it. You are simply less hungry when the second and third meals roll around. [This may explain why even these highly disciplined athletes required weekly coaching by dietitians to keep their caloric intake constant.]

And when the investigators looked at changes in body weight over the 12-month period:

  • The TRE group lost 3.4% of their body weight.
    • Most of that weight loss was due to a decrease in fat mass, but there was also a loss of muscle mass.
  • In contrast the ND group increased their total body weight by 3.4%.
    • In other words, at the end of 12 months the difference between the TRE and ND groups amounted to almost 7% of their body weight. This difference was highly significant.
    • Most of the increase in body weight in the ND group was due to a 2.9% increase in muscle mass.

These results are also consistent with the findings of earlier studies of time-restricted eating.

The observed decrease in body weight and fat mass is important because whenever you decrease body weight and fat mass, you:

  • Reduce inflammatory markers.
  • Improve blood sugar control.
  • Improve lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

Of course, that still sounds pretty good. Who wouldn’t want to lose weight and get healthier? But are the weight reduction and health benefits unique to time-restricted eating? That is the claim of those who promote this diet.

But is it true? To answer that question, we need to take a broader view of popular diets. We need to ask, “Is something special about time-restricted eating, or would other restrictive diets give similar results?”

Are The Benefits Of Time-Restricted Eating An Illusion?

The TruthThere are two diet truths that nobody is talking about:

1) Forget the metabolic mumbo-jumbo. The primary reason restrictive diets cause you to lose weight is that you unconsciously eat less while you are on these diets.

For time-restricted eating, you eat less because you have restricted the time when you can eat. With other restrictive diets, you have restricted the foods you can eat. The reason why that causes you to eat less is more subtle. I call it the “Bagels and Cream Cheese Effect”.

    • When you go on a low-fat diet, it sounds great to say you can eat all the bagels you want. But without the cream cheese, bagels become boring, and you eat less.
    • When you go on a low-carb diet, it sounds great to say you can eat all the cream cheese you want. But without the bagels, cream cheese becomes boring, and you eat less.

2) The proponents of fad diets make them look good by comparing them to the typical American diet. Anything is better than the American diet. However, when you make the comparisons based on the reduction in caloric intake or the amount of weight lost, the health benefits of popular diets are virtually identical. For example:

    • When you compare the Atkins diet and other low carb diets with the typical American diet, inflammation is lower on the low carb diets. However, one recent study compared people on the Atkins diet with people who had lost an equal amount of weight on a balanced diet that included all food groups. Guess what? Inflammation is much higher on the Atkins diet when you compare it to a healthy diet that gives equal weight loss.
    • This study reported that the time-restricted eating group ate less, lost more weight, and had better health parameters than the control group. However, previous studies that compared time-restricted eating with groups that reduced caloric intake to the same extent by simply counting calories have found the two groups had identical weight loss and improvement in health parameters.

In other words, there is nothing magical about time-restricted eating. Any diet that causes you to eat less will give identical results. There are only two questions left:

  1. Can you stick with time-restricted eating long term?

Time-restricted eating is not everyone’s cup of tea. But this study suggests that if you can stick with it better than with other restrictive diets, you are likely to lose weight and reap some health benefits.

2) Should you stick with time-restricted eating long term?

To answer this question, you need to know whether there are any downsides to time-restricted eating.

Does Time-Restricted Eating Have A Downside?

thumbs down symbolOf course, most people would consider weight loss and an improvement in health parameters as a definite plus. It’s all good. Or is it? Does time-restricted eating have any downsides? This study identified two potential downsides:

1) Decreased anabolic hormones.

    • Anabolic hormones (hormones that stimulate an increase in muscle mass) were decreased in the TRE group. Specifically:
      • Testosterone was decreased by 17% at the end of 12 months in the TRE group.
      • Insulin-like growth factor-1 (IGF-1) was decreased by 14% in the TRE group.
    • Both anabolic hormone levels were unchanged in the ND group.

2) Decreased muscle mass. Between months 2 and 12:

    • Muscle mass was decreased by 2.3% in TRE group and increased by 2.9% in the ND group.
    • The cross-sectional area of arm and thigh muscles was decreased by an average of 4.3% in the TRE group and increased by an average of 8.5% in the ND group.

In the words of the authors, “With our results, we confirmed that a long-term TRE protocol could impair the ability of maintaining muscle mass, possibly because of a reduction in caloric intake and a direct effect of fasting on the production of anabolic hormones.”

That is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. So, a continuous increase in muscle mass and cross-sectional area would be expected. This was seen in the ND group but not in the TRE group, which actually lost muscle mass. The average “Joe” or “Jane” would likely lose even more muscle on this diet.

And continuous, long-term loss of muscle mass has significant health consequences including:

  • Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
  • Decreased insulin sensitivity, which increases the risk of diabetes.
  • Increased risk of osteoporosis.
  • Muscle weakness, which increases the risk of falling.

Dr. Paoli, the lead scientist on this study, was quoted as saying, “The main take home message is that there are pros and cons to prolonged time-restricted eating. Although time-restricted eating may produce some physiological advantages, it is not a miracle as often suggested in social media posts.”

The Bottom Line 

A recent study looked at the pros and cons of following a time-restricted eating (TRE) diet compared to a diet with normal meal distribution (ND) for 12 months.

  • The TRE group had reduced inflammation, better blood sugar control, and better lipid profiles than the ND group.

However, the improved health parameters were not caused by some magical metabolic changes due to fasting.

  • The TRE group unconsciously reduced their caloric intake and lost weight compared to the ND group. And any time you lose weight, you get reduced inflammation, better blood sugar control, and better lipid profiles.

In the words of the authors, “…it is plausible that the caloric reduction observed in the TRE group may have contributed to the reductions in body mass and additional health benefits…”

And there is nothing unique about time-restricted eating.

  • Any restrictive diet is likely to give similar results. (For more details, read the article above.)

Finally, there were some significant downsides to time-restricted eating.

  • The TRE group had a reduction in anabolic hormones and lost muscle mass.

In the words of the authors, “With our results, we confirmed that a long-term TRE protocol could impair the ability of maintaining muscle mass, possibly because of a reduction in caloric intake and a direct effect of fasting on the production of anabolic hormones.”

This is putting it mildly. The participants in this study were engaged in a rigorous 3-times/week strength training program specifically designed to increase muscle mass and were consuming over 100 grams of protein a day. They should have gained muscle mass. Instead, they lost it.

Continuous, long-term loss of muscle mass has significant health consequences including:

  • Decreased metabolic rate, which makes it more difficult to maintain a healthy weight.
  • Decreased insulin sensitivity, which increases the risk of diabetes.
  • Increased risk of osteoporosis.
  • Muscle weakness, which increases the risk of falling.

Dr. Paoli, the lead scientist on this study, was quoted as saying, “The main take home message is that there are pros and cons to prolonged time-restricted eating. Although time-restricted eating may produce some physiological advantages, it is not a miracle as often suggested in social media posts.”

For more details 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.

Are Carnitine Supplements Good For You Or Bad For You?

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What Is The Truth About Carnitine And TMAO?

BodybuilderIf you are a weightlifter or bodybuilder, chances are you are taking an L-carnitine supplement or a protein shake fortified with L-carnitine. That is because L-carnitine has been promoted for increasing muscle mass and physical performance for so long that most people have come to believe it must be true. Is it true, or is it just another food myth?

If you visit Dr. Strangelove’s website, you may also be told that carnitine supplementation is beneficial for weight loss, migraines, baldness, ADHD and autism, chronic fatigue syndrome, and/or low energy, muscle loss, and cognitive decline in older adults. Are these claims fact or fiction?

On the flip side, recent studies have suggested that the carnitine in red meat might be bad for your heart. Could the same be true for carnitine supplements? Could they also be bad for your heart?

A recent systematic review (AG Sawicka et al, Journal of the International Society of Sports Nutrition, 17: 49, 2020) of L-carnitine supplementation answers these important questions. The authors called their study “The bright and dark sides of L-carnitine supplementation” because they set out to systematically investigate the benefits and potential risks of L-carnitine supplementation.

But before I share the results of this study, I need to give you a little background on L-carnitine. It is time for another Biochemistry 101 segment.

Biochemistry 101: What You Need To Know About Carnitine

professor owlCarnitine plays an essential role in human metabolism. It is required for transport of fatty acids into our mitochondria so they can be used to generate energy. Without carnitine we would be unable to utilize most of the fats in our diet as an energy source.

As you might expect, carnitine is essential for any tissues that have mitochondria, but it is particularly important for high energy tissues like skeletal and heart muscle.

For most of us, our liver and kidneys make all the carnitine we need. So, we don’t really need carnitine from food or supplements.

However, we do get significant amounts of carnitine from red meat, much smaller amounts of carnitine from other animal foods, and almost no carnitine from plant foods. Adults consuming diets with red meat and other animal foods get about 60-180 mg of carnitine a day from their diet, whereas vegans only get around 10-12 mg/day.

Uptake of carnitine from the blood into muscle tissues requires insulin. Thus, carnitine uptake into muscle is significantly less on a low-carbohydrate or keto diet than it is on a mixed diet containing carbohydrates.

Finally, our kidneys do an excellent job of regulating blood carnitine levels, with excess carnitine being excreted into the urine. Thus, total body carnitine levels are virtually the same with high-carnitine and low-carnitine diets.

Question MarkThis raises the question: “Are L-carnitine supplements good for you?”

Now, let’s talk about the dark side of carnitine. I have discussed this in a previous issue of “Health Tips From the Professor”. Here is a brief summary:

  • People who eat a lot of red meat harbor a species of bacteria in their intestine that converts carnitine to trimethylamine (TMA). We don’t know whether this species of gut bacteria is favored by the presence of red meat in the diet or the absence of certain fruits, whole grains, and legumes from the diet of meat eaters.
  • The TMA is reabsorbed into the bloodstream, and the liver converts TMA to TMAO (trimethylamine N-oxide).
  • TMAO is associated with an increased risk of heart attack, stroke, and heart failure.

When you think about it, this is a perfect example of double jeopardy. Red meat is high in carnitine, and red meat eaters have gut bacteria that result in carnitine being converted to a compound that may increase the risk of heart disease.

This raises the question: “Are L-carnitine supplements bad for you?”

Let’s look at these two questions. First, I will discuss the recent review. Then I will put the conclusions of that review into perspective by looking at what other health experts say.

Are Carnitine Supplements Good For You Or Bad For You?

good news bad newsMost previous studies of carnitine supplementation have lasted only two or three weeks, which may not be long enough to measure an effect of carnitine supplementation on performance. So, the authors of this review paper selected studies that lasted 11 weeks or more for their review.

The review included 11 studies. They lasted either 12 or 24 weeks. Participants received doses ranging from 1 gm to 4.5 gm of L-carnitine per day. Here are the conclusions of the review:

  • Participants receiving L-carnitine alone had no increase in muscle carnitine content.
  • Participants receiving L-carnitine + 80 grams of carbohydrate had around a 10% increase in muscle carnitine content. [To put that into perspective, 80 grams of carbohydrate is roughly equivalent to 2 cups of white rice or two medium potatoes.]
  • One study compared male vegetarians with male omnivores. The omnivores had no increase in muscle carnitine content, but the vegetarians did. [The study did not analyze the diets of the omnivores and vegetarians, but it is probably safe to assume that the carbohydrate content was higher on the vegetarian diet.]
  • There was no significant effect of L-carnitine on muscle mass or physical performance. [This is logical, given the minimal effect of L-carnitine supplementation on muscle carnitine levels.

Thus, this review found little evidence that L-carnitine supplementation was good for you. It resulted in little or no increase in muscle carnitine levels or in physical performance.

  • Two of the 11 studies measured plasma TMAO levels. These studies found that L-carnitine supplementation resulted in a significant increase in plasma TMAO levels.

Thus, this review found some evidence that L-carnitine supplementation might be bad for you.

What Is The Truth About Carnitine And TMAO?

the truth signIs carnitine good for you? With respect to this question, the conclusions of this review are similar to the conclusions of other health experts. For example, in their Fact Sheet On Carnitine For Health Professionals the NIH states “Some athletes take carnitine to improve performance. However, twenty years of research finds no consistent evidence that carnitine supplements can improve exercise or physical performance in healthy subjects—at doses ranging from 2–6 grams/day administered for 1 to 28 days. For example, carnitine supplements do not appear to increase the body’s use of oxygen or improve metabolic status when exercising, nor do they necessarily increase the amount of carnitine in muscle.”

The NIH fact sheet goes on to list some diseases causing muscle loss or muscle weakness, for which L-carnitine supplementation is appropriate. However, in these cases, the carnitine supplementation should be recommended by health professionals.

Is carnitine bad for you? The TMAO story is a bit more complicated. As I mentioned above, there is an association between red meat consumption and blood TMAO levels and an association between blood TMAO levels and heart disease.

Is it TMAO that increases the risk of heart disease or is it some other component (saturated fat, for example) of red meat that increases the risk of heart disease? Nobody knows. More research is needed.

There is also a “red herring” that complicates the TMAO story. It turns out that TMAO helps fish survive the high pressures they encounter in the deep ocean. Thus, many fish are high in TMAO, and fish consumption also increases blood TMAO levels.

Are the bad effects of TMAO in fish outweighed by the heart healthy components in fish (omega-3s, for example)? Nobody knows. More research is needed.

To summarize:

  • There is no reason to take L-carnitine supplements unless directed by your health professional. There is little evidence they will help your physical performance. There is also no good evidence to support the other benefits of L-carnitine you find listed on Dr. Strangelove’s blog or the website of your favorite supplement company.
  • L-carnitine supplements may be bad for your heart, but much more research will be needed to be sure. [Note: Based on what we know about the role of gut bacteria in TMAO production, vegans could probably take l-carnitine supplements without causing an increase in TMAO levels. However, that is probably a moot point. There is no evidence that L-carnitine is more effective for vegans than it is for omnivores.]

The Bottom Line 

If you are a weightlifter or bodybuilder, chances are you are taking an L-carnitine supplement or a protein shake fortified with L-carnitine. That is because L-carnitine has been promoted for increasing muscle mass and physical performance for so long that most people have come to believe it must be true. Is it true, or is it just another food myth?

On the flip side, recent studies have suggested that the carnitine in red meat might be bad for your heart. Could the same be true for L-carnitine supplements? Could they also be bad for your heart?

A recent review looked at these questions. Here are the conclusions of the review:

  • Participants receiving L-carnitine alone had no increase in muscle carnitine content.
  • Participants receiving L-carnitine + 80 grams of carbohydrate had around a 10% increase in muscle carnitine content. [To put that into perspective, 80 grams of carbohydrate is roughly equivalent to 2 cups of white rice or two medium potatoes.]
  • There was no significant effect of L-carnitine on muscle mass or physical performance. [This is logical, given the minimal effect of L-carnitine supplementation on muscle carnitine levels.

Thus, this review found little evidence that L-carnitine supplementation was beneficial. It resulted in little or no increase in muscle carnitine levels or in physical performance.

  • This review also found that L-carnitine supplementation resulted in a significant increase in plasma TMAO, a compound that has been associated with an increased risk of heart disease.

Thus, this review found some evidence that L-carnitine supplementation might be bad for you.

The NIH has also issued a fact sheet for health professionals summarizing research on L-carnitine over the past 20 years. The conclusions from their fact sheet can be best summarized as:

  • There is no reason to take L-carnitine supplements unless directed by your health professional. There is little evidence they will help your physical performance. There is also no good evidence to support the other benefits of L-carnitine you find listed on Dr. Strangelove’s blog or the website of your favorite supplement company.
  • L-carnitine supplements may be bad for your heart, but much more research will be needed to be sure.

For more details 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.

Does Leucine Trigger Muscle Growth?

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What Does The Perfect Post-Workout Protein Shake Look Like?

Author: Dr. Stephen Chaney

 Post-Workout Protein ShakeIf you work out on a regular basis and read any of the “muscle magazines”, you’ve seen the ads. “Explode Your Muscles.” “Double Your Gains.” They all claim to have the perfect post-workout protein shake, backed by science. They all sound so tempting, but you know that some of them have to be scams.

I told you about some of the sports supplements to avoid in a previous “Health Tips From the Professor”. In this issue, I’m going to ask “What does the perfect post-workout protein shake look like?”

For years athletes have been using protein beverages containing branched chain amino acids after their workouts to maximize muscle gain and recovery. There was some science behind that practice, but the major questions were unanswered. Nobody really knew:

  • How much protein is optimal?
  • What kind of protein is optimal?
  • What amount of branched chain amino acids is optimal?
  • Are some branched chain amino acids more important than others?
  • Does the optimal amount of branched chain amino acids depend on the amount of protein?

As a consequence, after workout protein supplements were all over the map in terms of protein source, protein amount, branched amino acid amount and type of branched chain amino acids. Fortunately, recent research has clarified many of these questions.

How Much And What Kind Of Protein Do You Need?

  • Recent research has shown that the optimal protein intake for maximizing muscle gain post workout is 15-20 gm for young adults (Katsanos et al, Am J Clin Nutr 82: 1065-1073, 2005; Moore et al, Am J Clin Nutr, 89: 161-168, 2009) and 20-25 gm for older adults (Symons et al, Am J Clin Nutr 86: 451-456, 2007).
  • More protein isn’t necessarily better. The effect of protein intake on post workout muscle gain maxes out at around 25 gm for young adults and 30 gm for older adults (Symons et al, J Am Diet Assoc 109: 1582-1586, 2009).
  • Whey protein is the best choice for enhancing muscle gain immediately after a workout. Other protein sources (soy, casein, chicken) are better choices for sustaining muscle gain over the next few hours.

Does Leucine Trigger Muscle Growth?

  • It turns out that leucine is the only branched chain amino acid that actually stimulates muscle protein synthesis (Am J Physiol Endocrinol Metab 291: E381-E387, 2006). And protein is what gives muscles their strength and their bulk.
  • Recent research has shown that 2-3 gm of leucine (2 gm for young adults; 3 gm for older adults) is sufficient to maximize post workout muscle gain if protein levels are adequate (Am J Physiol Endocrinol Metab 291: E381-E387, 2006).

Unanswered Questions About Optimizing Muscle Gain Post-Workout

  •  Do the other branched chain amino acids play a supporting role, or is leucine alone sufficient to drive post-workout muscle gain?
  • Can leucine still help maximize post-workout muscle gain if protein intake is inadequate? If so, how much leucine is needed?

Does Leucine Enhancement Improve Low Protein Shakes?

Lrg Extension ExercisesA recent study (Churchward-Venne et al, Am J Clin Nutr, 99: 276-286, 2014) seems to answer those two questions. The authors compared the effect of 5 protein-amino acid combinations on muscle protein synthesis in 40 young men (~21 years old) following unilateral knee-extensor resistance exercise. The protein shakes contained:

  • 25 gm of whey protein, which naturally contains 3 gm of leucine (high protein)
  • 6.25 gm of whey protein, which naturally contains 0.76 gm of leucine (low protein)
  • 6.25 gm of whey protein with 3 gm of leucine (low protein, low leucine)
  • 6.25 gm of whey protein with 5 gm of leucine (low protein, high leucine)
  • 6.25 gm of whey protein with 5 gm of leucine + added isoleucine and valine (the other branched chain amino acids). (low protein, branched chain amino acids).

The results were clear cut:

  • The high protein shake (25 gm of protein) was far superior to the low protein shake (6.25 gm of protein) at enhancing post workout protein synthesis. This is consistent with numerous other published clinical reports.
  • Adding 3 gm of leucine to the low protein shake had no effect on post-workout protein synthesis, but 5 gm of added leucine made the low protein shake just as effective as the high protein shake at supporting post-workout protein synthesis.

In short, leucine can improve the effectiveness of a low protein shake, but you need more leucine than if you chose the high protein shake to begin with.

  • Adding extra branched chain amino acids actually suppressed the effectiveness of leucine at enhancing post-workout protein synthesis. These data suggest:
    • Leucine probably is the major amino acid responsible for the muscle gain reported in many of the previous studies with branched chain amino acids.
    • If the other branched chain amino acids play a supporting role in the muscle gain, the quantities that occur naturally in the protein are probably enough. Adding more may actually reduce the effectiveness of leucine at stimulating muscle gain.

While this is a single study, it is consist with numerous other recent clinical studies. It simply helps clarify whether leucine can increase the effectiveness of a low protein supplement. It also clarifies the role of branched chain amino acids.

Also, while this study focused on protein synthesis, numerous other studies have shown that optimizing post-workout protein and leucine intake results in greater muscle gain (for example, Westcott et al., Fitness Management, May 2008)

The Bottom Line

Research on post-workout nutrition to optimize muscle gain from the workouts has come a long way in recent years. It is now actually possible to make rational choices about the best protein supplements and foods to support your workouts.

  • If you are a young adult (17-30), you should aim for 15-20 gm of protein and about 2 gm of leucine after your workout.
  • If you are an older adult (50+), you should aim for 20-25 gm of protein and 3 gm of leucine after your workout.
  • If you are in between you are on your own. Studies haven’t yet been done in your age group, but it’s reasonable to assume that you should aim for somewhere between the extremes.
  • If you are getting the recommended amounts of whey protein, the leucine level will also be optimal. If you are using other protein sources you may want to choose ones with added leucine.
  • The research cited above shows that you can make a low protein supplement effective by adding lots of leucine, but that’s going to require artificial flavors and sweeteners to cover up the taste of that much leucine. I would recommend choosing one that provided adequate protein to begin with.
  • While the research in this area is still somewhat fluid, I would avoid protein supplements with added branched chain amino acids other than leucine. If the paper I cited above is correct you probably get all of the other branched chain amino acids you need from your protein and adding more may actually interfere with the effect of leucine on muscle gain.
  • I’d pretty much forget all the other “magic ingredients” in post-workout supplements. If you’re a novice there is some evidence that arginine and HMB may be of benefit, but if you have been working out for more than 6 months, the evidence is mixed at best. As for the rest, the clinical studies are all over the map. There’s no convincing evidence that they work.
  • Whey protein is the best choice for enhancing muscle gain immediately after your workout. Soy and casein are better choices for sustaining muscle gain over the next few hours. If you’re looking at meat protein, chicken is a particularly good choice. Four ounces of chicken will provide the protein and leucine you need to sustain muscle gain for several hours.
  • Even if you are not working out, recent research on dietary protein and leucine has important implications for your health. In a recent “Health Tips From the Professor” I shared research showing that optimizing protein and leucine intake helps to increase muscle retention and maximize fat loss when you are losing weight.

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.

Are High Protein Diets Your Secret To Successful Weight Loss?

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Do High Protein Diets Reduce Fat And Preserve Muscle?

Author: Dr. Stephen Chaney

Healthy Diet food group, proteins, include meat (chicken or turkAre high protein diets your secret to healthy weight loss? There are lots of diets out there – high fat, low fat, Paleolithic, blood type, exotic juices, magic pills and potions. But recently, high protein diets are getting a lot of press. The word is that they preserve muscle mass and preferentially decrease fat mass.

If high protein diets actually did that, it would be huge because:

  • It’s the fat – not the pounds – that causes most of the health problems.
  • Muscle burns more calories than fat, so preserving muscle mass helps keep your metabolic rate high without dangerous herbs or stimulants – and keeping your metabolic rate high helps prevent both the plateau and yo-yo (weight regain) characteristic of so many diets.
  • When you lose fat and retain muscle you are reshaping your body – and that’s why most people are dieting to begin with.

So let’s look more carefully at the recent study that has been generating all the headlines (Pasiakos et al, The FASEB Journal, 27: 3837-3847, 2013).

The Study Design:

This was a randomized control study with 39 young (21), healthy and fit men and women who were only borderline overweight (BMI = 25). These volunteers were put on a 21 day weight loss program in which calories were reduced by 30% and exercise was increased by 10%. They were divided into 3 groups:

  • One group was assigned a diet containing the RDA for protein (about 14% of calories in this study design).
  • The second group’s diet contained 2X the RDA for protein (28% of calories)
  • The third group’s diet contained 3X the RDA for protein (42% of calories)

In the RDA protein group carbohydrate was 56% of calories, and fat was 30% of calories. In the other two groups the carbohydrate and fat content of the diets was decreased proportionally.

Feet_On_ScaleWhat Did The Study Show?

  • Weight loss (7 pounds in 21 days) was the same on all 3 diets.
  • The high protein (28% and 42%) diets caused almost 2X more fat loss (5 pounds versus 2.8 pounds) than the diet supplying the RDA amount of protein.
  • The high protein (28% and 42%) diets caused 2X less muscle loss (2.1 pounds versus 4.2 pounds) than the diet supplying the RDA amount of protein.
  • In case you didn’t notice, there was no difference in overall results between the 28% (2X the RDA) and 42% (3X the RDA) diets.

Pros And Cons Of The Study:

  • The con is fairly obvious. The participants in this study were all young, healthy and were not seriously overweight. If this were the only study of this type one might seriously question whether the results were applicable to middle aged, overweight coach potatoes. However, there have been several other studies with older, more overweight volunteers that have come to the same conclusion – namely that high protein diets preserve muscle mass and enhance fat loss.
  • The value of this study is that it defines for the first time the upper limit for how much protein is required to preserve muscle mass in a weight loss regimen. 28% of calories is sufficient, and there appear to be no benefit from increasing protein further. I would add the caveat that there are studies suggesting that protein requirements for preserving muscle mass may be greater in adults 50 and older.

The Bottom Line:

1)    Forget the high fat diets, low fat diets, pills and potions. High protein diets (~2X the RDA or 28% of calories) do appear to be the safest, most effective way to preserve muscle mass and enhance fat loss in a weight loss regimen.

2)     That’s not a lot of protein, by the way. The average American consumes almost 2X the RDA for protein on a daily basis. However, it is significantly more protein than the average American consumes when they are trying to lose weight. Salads and carrot sticks are great diet foods, but they don’t contain much protein.

3)     Higher protein intake does not appear to offer any additional benefit – at least in young adults.

4)     Not all high protein diets are created equal. What some people call high protein diets are laden with saturated fats or devoid of carbohydrate. The diet in this study, which is what I recommend, had 43% healthy carbohydrates and 30% healthy fats.

5)    These diets were designed to give 7 pounds of weight loss in 21 days – which is what the experts recommend. There are diets out there promising faster weight loss but they severely restrict calories and/or rely heavily on stimulants, they do not preserve muscle mass, and they often are not safe. In addition they are usually temporary.  I do not recommend them.

6)    This level of protein intake is safe for almost everyone. The major exception would be people with kidney disease, who should always check with their doctor before increasing protein intake. The only other caveat is that protein metabolism creates a lot of nitrogenous waste, so you should drink plenty of water to flush that waste out of your system. But, water is always a good idea.

7)     The high protein diets minimized, but did not completely prevent, muscle loss. Other studies suggest that adding the amino acid leucine to a high protein diet can give 100% retention of muscle mass in a weight loss regimen – but that’s another story for another day.

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