vitamin K Archives - Health Tips From The Professor

Are Omega-3s Needed For Strong Bones?

September 16, 2025 by Dr. Steve Chaney

Why Are Omega-3s Needed For Strong Bones?

Author: Dr. Stephen Chaney

Osteoporosis is one of the dreaded diseases associated with aging.

Over 50% of women and 25% of men will develop osteoporosis in their lifetime.

And the risk of osteoporosis is highest for Caucasians.

Over 40% of white women and 13% of white men will develop an osteoporotic fracture in their lifetime.

And osteoporotic fractures can be deadly. Bone fractures increase the risk of death 3-5-fold within the next few months. Moreover, the quality of life is diminished, and the risk of death is elevated for years after the fracture occurs.

So, if you are like many people, you are doing all you can to keep your bones strong so you will minimize your chances of developing osteoporosis. You probably even have a check list:

Resistance exercise (strengthens the bones you pull on)……Check

Walking (strengthens hip and leg bones)………………………Check

Adequate calcium & vitamin D (essential for strong bones)…Check

Magnesium & vitamin K (also important for strong bones)…..Check

Adequate protein (Muscle pulling on bone strengthens it)…..Check

Adequate omega-3s………………………………………………What!!!

You probably didn’t know about omega-3s. But recent research suggests they may also play a role in building strong bones and preventing osteoporosis. For example, studies show that omega-3s may influence bone metabolism by:

Enhancing absorption of calcium from the intestine.

Reducing the rate at which bone is broken down.

Increasing the rate at which new bone is built.

But large-scale population studies showing that omega-3 intake influences the risk of developing osteoporosis are lacking. The study ( Z Liu et al, Frontiers In Nutrition, 11: 1467559, 2023) I am discussing today was designed to fill that gap.

But before I describe the study, I should give you a quick review of bone metabolism.

Biochemistry 101: Bone Metabolism

To truly understand osteoporosis and how to prevent it, you need to know a bit about bone metabolism. We tend to think of our bones as solid and unchanging, much like the steel girders supporting an office building. Nothing could be further from the truth. Our bones are dynamic organs that are in constant change throughout our lives.

Cells called osteoclasts constantly break down old bone (a process called resorption), and cells called osteoblasts replace it with new bone (a process called accretion). Without this constant renewal process our bones would quickly become old and brittle.

In short, our bones are not inert. They are in constant flux. If we exercise regularly and get enough calcium, vitamin D, magnesium, and vitamin K from our diet, bone metabolism looks like this as we age.

When we are young, osteoblast activity predominates, so accretion (the bone building process) exceeds bone resorption, and our bones grow in size and density.

When we are adults, osteoblast and osteoclast activity are in balance. Thus, bone accretion and resorption are in balance, and our bone density stays constant. The top portion of the picture above depicts what happens when osteoclast and osteoblast activity are in balance.

However, as we age osteoclast activity predominates, and we start to lose bone density. Eventually our bones look like Swiss cheese and break very easily. This is called osteoporosis. The bottom portion of the picture depicts this.

We should also think of our bones as calcium reservoirs. We need calcium in our bloodstream 24 hours a day for our muscles, brain, and nerves to function properly, but we only get calcium in our diet at discrete intervals. Consequently:

When we eat our body tries to store as much calcium as possible in our bones.

Between meals, we break down bone material so that we can release the calcium into our bloodstream that our muscle, brain & nerves need to function.

If we lead a “bone healthy” lifestyle, all of this works perfectly. We build strong bones during our growing years, maintain healthy bones during our adult years, and only lose bone density slowly as we age – maybe never experiencing osteoporosis. We always accumulate enough calcium in our bones during meals to provide for the rest of our body between meals.

I should note that this is the current paradigm for bone metabolism. The study I am discussing today is asking whether omega-3 fatty acids should also be considered as part of a bone-healthy lifestyle.

How Was This Study Done?

The investigators used data from NHANES (National Health And Nutrition Examination Survey), an ongoing study to assess the health and nutritional status of adults and children in the United States. Specifically, this study combined data from participants from the 2005-2010, 2013-2014, and 2017-2018 NHANES surveys.

The participants included in the survey:

Were greater than 50 years old.

Had completed two 24-hour dietary recall surveys to determine the omega-3 content of their diet (The average omega-3 intake of the two surveys was used for this study).

Had a bone mineral density (BMD) test performed using dual-energy X-ray absorptiometry (DXA) scans.

Participants were excluded from the study if they had incomplete diet or bone mineral density data or if they had a disease that affects bone metabolism.

A total of 8,889 participants were included in the study. They were divided into 3 categories based on their bone density:

Normal bone density (4,421 participants)
Osteopenia (3,952 participants)
Osteoporosis (516 participants)

Finally, the participants were divided into quartiles based on their omega-3 intake, and omega-3 intake was correlated with bone density.

Are Omega-3s Needed For Strong Bones?

The study results were as follows:

Omega-3 intake was inversely related to bone density. Simply put, that means:

- The highest intake of omega-3s was observed in the group with normal bone density, and…

- The lowest omega-3 intake was observed in the osteoporosis group.

When the participants were divided into quartiles based on their omega-3 intake:

Participants with the highest omega-3 intake were 29% less likely to develop osteoporosis than participants with the lowest omega-3 intake.

When the investigators looked at subgroups, they found stronger effects of omega-3s on osteoporosis risk for women, people under 60, and non-smokers. Specifically:

Women with the highest omega-3 intake were 35% less likely to develop osteoporosis.

People under 60 were 49% less likely to develop osteoporosis.

Non-smokers were 36% less likely to develop osteoporosis.

The investigators concluded, “This study demonstrates a significant inverse relationship between dietary omega-3 fatty acid intake and osteoporosis risk, suggesting omega-3s play a crucial role in bone health. However, further longitudinal studies are needed to confirm these studies and refine dietary recommendations for osteoporosis prevention.”

Why Are Omega-3s Needed For Strong Bones?

You are probably thinking,

“Calcium and magnesium are part of bone structure. Vitamin D and vitamin K facilitate the incorporation of calcium into bone. So, it is logical that these nutrients would be important for strong bones.”

“But what role do omega-3s play? They aren’t incorporated into bone, and they don’t affect calcium metabolism.”

Here is what the authors said about that:

Omega-3s are anti-inflammatory. They decrease production of the pro-inflammatory cytokines that stimulate osteoclasts – the cells that break down bone.

EPA and DHA are also converted to prostaglandins that stimulate osteoblasts – the cells that build new bone.

Finally, the authors said, “Omega-3 fatty acids, especially EPA and DHA, have been shown to enhance calcium absorption in the gut – a process crucial for maintaining optimal bone mineral density…Omega-3s …do this by altering the lipid composition of cell membranes, thereby affecting calcium channels and enhancing calcium availability for bone tissue.”

Let me help you understand that statement.

While we might think of our cell membranes as rigid structures, they are quite fluid. The closest analogy I can think of is a large lake. You may not see any waves or ripples, but if a leaf drops on the surface it doesn’t stay in one place. It moves. We can think of calcium channels in our membrane like leaves on the water. They move across the cell membrane.

How fast they move depends on the fluidity of the cell membrane. This is determined by the lipids (fats) in the cell membrane, which in turn is determined by the fats in our diet. This is the one case where it is literally true that we are what we eat.

- When we have lots of saturated fats in our cell membranes, fluidity is low, and calcium channels move slowly across the membrane.

- When we have omega-3 fats in our cell membrane, fluidity is high, and calcium channels move quickly across the cell membrane.

Calcium channels work best when they cluster together, and this works best with highly fluid, omega-3-rich cell membranes.

What Does This Mean For You?

This study strongly suggests that omega-3s play a role in bone health, and they may be important for reducing our risk of osteoporosis. The authors concluded, “The findings suggest that omega-3 fatty acids play a critical role in bone health, supporting the need for dietary recommendations that encourage omega-3 consumption as a preventative measure against osteoporosis.”

However, this is the first study of its kind, which is why the authors said, “Further longitudinal studies are needed to confirm these findings.”

However, my biggest concern with the study is that it did not include information on the intake of the other nutrients essential for bone health (calcium, vitamin D, magnesium, and vitamin K). We don’t know at present the importance of omega-3s for preventing osteoporosis relative to dietary intake of other bone-healthy nutrients. For example:

Are omega-3s important for bone health when intake of calcium and/or the other bone-healthy nutrients are low?

Or are omega-3s equally important for bone health under all conditions?

However, the good news is that omega-3s have many proven health benefits such as heart health, controlling blood pressure, and reducing inflammation. If they are also important for bone health, we can consider it an unexpected benefit.

With that in mind, there are two important takeaways for you:

Omega-3s were most effective at preventing osteoporosis in people under 60. That is entirely consistent with what we know about preventing osteoporosis. The best prevention strategy is to build strong bones while you are young and maintain strong bones as long as possible in your adult years.

The optimal reduction of osteoporosis risk in this study was seen with an omega-3 intake of 1.86 g/d. While more studies are needed to define the optimal dose of omega-3s for reducing osteoporosis risk, this dose is within the “sweet spot” for the other omega-3 benefits I mentioned.

The Bottom Line

A recent study asked whether omega-3 fatty acids reduce the risk of osteoporosis.

The study found:

Omega-3 intake was inversely related to bone density.

When the participants were divided into quartiles based on their omega-3 intake:

Participants with the highest omega-3 intake were 29% less likely to develop osteoporosis than participants with the lowest omega-3 intake.

When the investigators looked at subgroups, they found stronger effects of omega-3s on osteoporosis risk for women, people under 60, and non-smokers.

The investigators concluded, “This study demonstrates a significant inverse relationship between dietary omega-3 fatty acid intake and osteoporosis risk, suggesting omega-3s play a crucial role in bone health. This supports the need for dietary recommendations that encourage omega-3 consumption as a preventative measure against osteoporosis.”

For more information on this study, why omega-3s reduce osteoporosis risk, and what this study means for you, read the article above.

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

_____________________________________________________________________________

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

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

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

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

______________________________________________________________________

About The Author

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

Prenatal Supplements Strike Out Again

May 9, 2023 by Dr. Steve Chaney

Is It Three Strikes And You Are Out?

Author: Dr. Stephen Chaney

If you are pregnant, you want the best for your unborn baby. Your doctor has recommended a prenatal supplement, but do the prenatal supplements on the market meet your needs? A few months ago, I shared two studies that concluded that most prenatal supplements on the market are woefully inadequate.

In fact, the authors said, “[Our] analysis found that prenatal supplements vary widely in content, often only contain a subset of essential vitamins, and the levels were often below…recommendations.”

In other words, their study found that most prenatal vitamins on the market may not be adequate to support your needs and the needs of your child through pregnancy and breastfeeding.

Now, a third study on the topic has been published (KA Saunders et al, American Journal of Clinical Nutrition, 117: 823-829, 2023. It differs from the previous studies in that:

1) The previous two studies took a comprehensive approach, while this study focused on 6 key nutrients.

The previous studies included all nutrients important for a healthy pregnancy including choline, iodine, and vitamin K, which have only recently been shown to be important for a healthy pregnancy.

This study focused on 6 nutrients, vitamin A, vitamin D, folic acid, calcium, iron, and omega-3 fatty acids, which have long been recognized as essential for a healthy pregnancy.

2) The previous two studies focused on prenatal supplements, while this study focused on all supplements that might be taken by pregnant women.

3) The previous two studies asked whether supplements provided recommended amounts of all nutrients needed for a healthy pregnancy. This study took a “Goldilocks approach” and asked whether levels of these 6 essential nutrients were appropriate (“just right”). The study:

Started by determining the intake of these 6 key nutrients by American women. The authors of the study then added the amount of each nutrient provided by the supplements in their study to the amount of that nutrient in the diet of American women and:

- Calculated the minimum amount of each nutrient that would be needed to assure that 90% of American women taking a particular supplement would meet the recommended intake for pregnant and lactating women.

- Calculated the maximum amount of each nutrient provided by supplements in their study to assure that that 90% of American women taking that supplement would not get potentially toxic amounts of that nutrient.

In other words, for each of the 6 nutrients they calculated a supplemental dose range that was neither too low nor too high. They called this the “appropriate dose range” for each nutrient. Goldilocks would have called it “just right”.

I’m sure you are anxiously waiting to learn what their study found. But before we go there, I will describe how the study was done.

How Was The Study Done?

For the dietary intake portion of the study, the authors used dietary intake data previously collected from the Environmental Influences on Child Health Outcomes (ECHO) study.

The ECHO study is a consortium of 69 medical centers across multiple states. It is an observational study of mothers and their offspring designed to understand the effects of early life exposures on child health and development.

The current study analyzed dietary intake data for 2450 participants from 6 medical centers across 5 states in the ECHO study. The women in this study were diverse with respect to ethnicity, education, and weight.

All pregnant women in the current study completed at least one 24-hour dietary recall between 6-week gestation until delivery (24% completed one dietary recall. 76% completed two or more dietary recalls). Dietary intake was generally assessed with an expert interviewer and included all foods and beverages consumed in the previous 24 hours.

For the supplement portion of the study, the authors used the NIH Dietary Supplement Label Database because it is the most complete listing of supplements in the US. The authors selected 20,547 supplements that contained at least one of the 6 essential nutrients from this database.

To determine which of the 20,547 supplements contained appropriate levels of the 6 nutrients (vitamin A, vitamin D, folic acid, calcium, iron, and omega-3 fatty acids) selected for this study, the authors used the process described in the introduction above. Briefly:

The authors added the amount of each nutrient provided by the supplements in their study to the amount of that nutrient in the diet of American women and:

Calculated the minimum amount of each nutrient that would be needed to assure that 90% of American women taking a particular supplement would meet the recommended intake for pregnant and lactating women.

Calculated the maximum amount of each nutrient provided by supplements in their study to assure that that 90% of American women taking that supplement would not get potentially toxic amounts of that nutrient.

In other words, for each of the 6 nutrients they calculated a supplemental dose range that was neither too low nor too high. They called this the “appropriate dose range” for each nutrient.

Why Are The 6 Nutrients Included In This Study Important?

Dietary Intake Is Often Inadequate

The diet analysis of pregnant American women in this study found:

42% were at risk of inadequate vitamin A intake.

96% were at risk of inadequate vitamin D intake.

45% were at risk of inadequate folic acid intake.

55% were at risk of inadequate calcium intake.

93% were at risk of inadequate iron intake.

67% were at risk of inadequate omega-3 intake.

The percentage of women at risk for inadequate intake of these nutrients varied with age, ethnicity, and income levels. But the overall message is clear. Most American women are not getting enough of these essential nutrients from their diet alone.

The Risk of Inadequate and Excessive Intake Of These Nutrients

These 6 nutrients were chosen in part because reviews by the Cochrane Collaboration have concluded that inadequate intake of these nutrients are associated with complications during pregnancy and delivery. They can also adversely affect the health and normal development of the baby.

This is important because the Cochrane Collaboration is considered the Gold Standard of clinical studies. You can find a more detailed description of Cochrane Collaboration studies and why they are the Gold standard here.

[Note: The Cochrane Collaboration has not yet evaluated choline, iodine, and vitamin K for pregnant women, but their inclusion in prenatal supplements is supported by multiple clinical studies.]

In addition, excess intake of all these nutrients except omega-3s can harm both the fetus and the mother. The is why the Food and Nutrition Board has set ULs (Upper Limits – the level above which toxicity can occur) for 5 of the 6 nutrients. This is important because previous studies have suggested that up to 25% of women may be getting toxic levels of one or more of these nutrients when you consider both their dietary intake and their prenatal supplement.

Summary

In other words, both too little and too much of these nutrients can harm the mom and her baby. It is critical that prenatal supplements get the dosing right.

It is for that reason that the authors of this study have set an “appropriate dose range” (high enough that 90% of women have enough of each nutrient to prevent deficiency and low enough that 90% of women do not exceed the UL for each nutrient) as the standard for evaluating the adequacy and safety of supplements for pregnant women.

Prenatal Supplements Strike Out Again

Of the 20,547 supplements (421 labeled as prenatal supplements) available on the US market as of December 31, 2022, the investigators reported that:

Only 69 (0.3%) supplements contained all 6 nutrients considered essential for a healthy pregnancy.

Only 1 supplement contained all 6 nutrients at the appropriate doses, and it wasn’t even labeled as a prenatal supplement.

In addition:

One supplement containing all 6 nutrients put 100% of the women in their study at risk for excessive intake of folic acid.

Another supplement containing all 6 nutrients put 46% of the women in their study at risk of inadequate calcium intake.

The authors concluded, “Almost no US dietary supplements provide key nutrients in the doses needed for pregnant women. Affordable and convenient products that fill the gap between food-based intake and estimated requirements of pregnancy without inducing excess intake are needed to support pregnant women and their offspring.”

In short, the conclusion of this study can be summed up as, “Prenatal Supplements Strike Out Again”.

[Note: It sometime takes a while for supplement labels to be posted in the NIH Dietary Supplement Label Database. The authors acknowledged that this study may not include supplements introduced or reformulated in the last quarter of 2022.]

Is It Three Strikes And You Are Out?

If you are pregnant or thinking of becoming pregnant, this should be a wake-up call.

70% of pregnant women in this country take prenatal supplements, usually based on recommendations by their health care provider. They assume the prenatal supplements meet their needs and the needs of their unborn baby.

Yet three studies evaluating the adequacy of prenatal supplements have been published in the past few months. They took very different approaches in evaluating the supplements. But all three studies concluded that the vast majority of prenatal supplements on the market are woefully inadequate.

You may be wondering, “Is it three strikes, and you are out?” Are there no decent prenatal supplements on the market? The answer to those questions is, “No. There are good prenatal supplements on the market.”

You may be wondering how I can say that in the face of such overwhelming negative data. That’s because while all 3 studies were very good studies, they each had “blind spots”:

1) Each of the studies used very stringent criteria for identifying adequate prenatal supplements. In some cases, their criteria were stricter than the RDA recommendations and the recommendations of the American College of Obstetrics and Gynecology for pregnant and lactating women. It could be argued that their criteria were too stringent.

2) In the case of the current study, it could also be argued that evaluating only 6 nutrients is not a good criterion for evaluating the adequacy of prenatal supplements. For example, I looked up the one supplement rated as adequate in this study. It does provide appropriate doses of the 6 nutrients this study focused on. It also provides appropriate doses of vitamin K and iodine. But it does not provide choline. It is a very good supplement for women, but it is not the perfect prenatal supplement.

So, what can you do? How can you find the best prenatal supplement for you? Unfortunately, you cannot rely on advice from your friends or your health professional. You cannot rely on advertisements. That is a good place to start, but you have to do your own sleuthing.

With that in mind, I have listed 7 simple rules for selecting the best possible prenatal supplement in my article about the first two studies. Use these rules for evaluating every prenatal supplement you come across. Happy sleuthing.

The Bottom Line

A recent study evaluated all 20,547 supplements on the US market to see if they met the needs of pregnant women in this country.

They focused on 6 nutrients (vitamin A, vitamin D, folic acid, calcium, iron, and omega-3s) known to be essential for a healthy pregnancy.

They determined the dietary intake for all 6 nutrients in a cross section of pregnant women in the US.

They added the amount of the 6 nutrients in each of the 20,547 supplements to the dietary intake of those nutrients by pregnant women.

They then asked which supplements provided the “appropriate dose” of all 6 nutrients. They defined “appropriate dose” as the dose range that was.

- High enough to prevent deficiency of that nutrient in 90% of pregnant women taking the supplement…and…

- Low enough to prevent toxicity from that nutrient in 90% of pregnant women taking the supplement.

In other words, for each of the 6 nutrients they calculated a supplemental dose range that was neither too low nor too high.

Of the 20,547 supplements (421 labeled as prenatal supplements) available on the US market:

Only 69 (0.3%) supplements contained all 6 nutrients they considered essential for a healthy pregnancy.

Only 1 supplement contained all 6 nutrients at the appropriate doses, and it wasn’t even labeled as a prenatal supplement.

If you are pregnant or thinking of becoming pregnant, this should be a wake-up call.

Yet three studies evaluating the adequacy of prenatal supplements have been published in the past few months. And all three studies concluded that the vast majority of prenatal supplements on the market are woefully inadequate.

You may be wondering how I can say that in the face of such overwhelming negative data. That’s because while all 3 studies were very good studies, they each had “blind spots”:

For more details on this study and 7 tips on finding the best prenatal supplement 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.

____________________________________________________________________________

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

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

Is Your Prenatal Supplement Adequate?

November 8, 2022 by Dr. Steve Chaney

What Should You Look For In A Prenatal Supplement?

Author: Dr. Stephen Chaney

You want to do the best for your unborn child. So, you try to find the best prenatal supplement. You may ask your doctor to recommend a prenatal supplement. You may ask your best friend what supplement she used when she was pregnant. Or perhaps you scan online reviews of prenatal supplements by random dietitians or nutrition gurus to select the “best” prenatal supplements.

Then you read the supplement label or the company’s website and see claims like:

“Supports optimal nutrition before, during, and after pregnancy”

“Packed with 16 nutrients to support fetal development, immunity, energy metabolism, and more”

“Concise prenatal formula supports both bone and brain development”

It sounds so good. You think you have found the perfect prenatal supplement. “Right?”

Perhaps not. A recent study (JB Adams et al, Maternal Health, Neonatology, and Perinatology, 8:4, 2022) did an in-depth review of prenatal supplement recommendations and how well prenatal supplements on the market met those recommendations.

The results were not encouraging. The authors concluded, “[Our] analysis found that prenatal supplements vary widely in content, often only contain a subset of essential vitamins, and the levels were often below…recommendations.”

In other words, their study found that most prenatal vitamins may not be adequate to support your needs and the needs of your child through pregnancy and breastfeeding.

I know this is likely to be a topic of great concern for many of you. So, I will examine the study in detail and give you some guidelines for selecting the perfect prenatal supplement.

How Was This Study Done?

This study can be divided into two parts.

#1: What Should The Ideal Prenatal Supplement Contain:

The authors started off by reevaluating the optimal recommendations for prenatal supplements. They reviewed over 200 articles, focusing on articles that:

Provided insight into optimal dosage [of essential nutrients] such as treatment studies on the effects of different doses on outcomes and biomarkers.

Were larger, more rigorously designed, such as randomized double-blind placebo-controlled studies.

The studies included in their review fell into three categories:

The association of low levels of vitamins with health problems [during pregnancy and in the child after birth].

2) Studies on the changes in [blood] vitamin levels during pregnancy [when the mother is either] un-supplemented or supplemented (The blood level of many vitamins decreases dramatically during pregnancy without supplementation).

3) Clinical trials on the effect of vitamin supplementation on health problems [during pregnancy].

They used these data to create their recommendations for what an ideal prenatal supplement should contain. In some cases, their recommendations were higher than current RDA recommendations for pregnant women.

#2: How Do Currently Available Prenatal Supplements Compare With Their Recommendations For The Ideal Supplement?

For this part of the study, they created a comprehensive list of the nutrients provided by 188 prenatal supplements currently on the market using databases created by the National Institutes of Health. Where these databases were outdated, the nutrient list for that supplement was updated using information on the manufacturer’s websites or labels on retail websites such as Amazon.

Finally, they compared the nutrient content of all 188 prenatal supplements with their recommendations for the ideal prenatal supplement.

Is Your Prenatal Supplement Adequate?

There are four points I wish to make before I review the results of this study.

I suspect you are most interested in finding out how prenatal supplements on the market compare with their recommendations for an ideal supplement, so that is what I will discuss below.

2) As I mentioned above, some of their recommendations exceed the current Daily Value (DV) recommendations for pregnant and lactating women. I will point that out whenever it significantly affects the comparisons.

3) The authors of this article made the point that most women going on a prenatal supplement will probably discontinue taking their multivitamin supplement. Thus, their recommendations included nutrients commonly included in multivitamin supplements. This is a valid point, and something you should consider when choosing a prenatal supplement. However, in my discussion below I will focus on the nutrients that are universally recognized as important for pregnancy and lactation.

4) The authors focused on prenatal supplements that had less than the recommended amount of essential nutrients. They did not ask how many of those supplements had excessive amounts of certain nutrients. In my non-systematic review of prenatal supplements, I found several that had doses of some nutrients in thousands of percent of the DV recommendations. In my opinion, this is potentially unsafe for pregnancy and nursing. I will cover this topic in more detail in my discussion.

With that in mind, here are the results of their review.

Vitamins:

When you look at vitamins that have long been recognized as essential for pregnant women, the results are encouraging:

Vitamin D, folate, vitamin B12, and vitamin B6 are found in adequate amounts compared to the DV in most prenatal supplements.

However, when you look at nutrients that have more recently been recognized as essential for pregnant women, the story is very different:

For vitamin K only 31% of prenatal supplements contain vitamin K and only 16% meet or exceed their recommendation for vitamin K.

- Their recommendation (90 mcg/day) is identical to the DV for vitamin K. So, there is no doubt that most prenatal supplements do not provide adequate amounts of vitamin K.

For choline only 40 % of prenatal supplements contain choline and only 2% meet or exceed their recommendation for choline.

- Their recommendation (350 mg/day) for choline is less than the 450 mg/day recommended by the NIH and the American College of Obstetricians and Gynecologists.

- The average prenatal supplement only provides 25 mg of choline, which is wildly inadequate by any standard.

For DHA only 42% of prenatal supplements contain DHA and only 1% meet or exceed their recommendation for DHA.

- Their recommendation (600 mg/day) for DHA is higher than the 200 – 300 mg/day recommended by the most health organizations.

- However, the average prenatal supplement only provides 94 mg of DHA, so even at 200 – 300 mg/day a substantial percentage of prenatal supplements do not provide adequate amounts of DHA.

Minerals:

This study did not consider minerals, so I will draw on another source to estimate the adequacy of minerals in prenatal supplements.

Three key minerals for a healthy pregnancy are iron, calcium, and iodine (Yes, I realize that iodine is not a mineral, but it is usually listed with the minerals on supplement labels. And it is also essential for a healthy pregnancy). Fortunately, another recent study (LG Saldanha et al, Journal of the American Academy of Dietetics, 117: 1429-1436, 2017) looked at the adequacy of these nutrients in 214 prenatal supplements. This study found:

The iron DV for pregnant and lactating women is 27 mg/day and 95% of prenatal supplements contained iron at the recommended level.

The calcium DV for pregnant and lactating women is 1,300 mg/day. A high percentage (91%) of prenatal supplements contain calcium, but many prenatal supplements only provide 100-200 mg of calcium. That is far less than the DV.

The situation for iodine is even more alarming. Only 50% of prenatal supplements contain iodine. And for those that do contain iodine, the average iodine content is only 150 mcg (The DV for pregnant and lactating women is 290 mcg/day).

It is no wonder the authors of these two studies concluded that most prenatal supplements on the market do not provide adequate amounts of all the nutrients needed for a healthy pregnancy. The shortfalls are particularly acute for vitamin K, choline, DHA, iodine, and calcium.

What Should You Look For In A Prenatal Supplement?

By now you are probably wondering how you know a good prenatal supplement from a bad one. Here are six simple rules for choosing the ideal prenatal supplement.

Don’t rely on health “gurus” to choose your prenatal supplement for you. I did a little “sleuthing” for you. I searched the internet for websites claiming to have identified the “best” prenatal supplements. I checked out the supplements they recommended, and here is what I found:

The supplements the gurus recommended checked all the boxes in that they had some of all the nutrients required for a healthy pregnancy.

However, the amount of those nutrients ranged from lows of 10-20% of the DV for pregnant and lactating women to thousands of percent of the DV for others.

In other words, they contained grossly inadequate levels of some nutrients and potentially toxic levels of others.

2) Don’t believe label claims or claims made on the manufacturer’s website. Remember the claim, “Concise prenatal formula supports both bone and brain development”, that I mentioned at the beginning of this article? The supplement associated with that claim had only 100 mg of calcium and no DHA. It is hard to imagine a supplement like that supporting either bone or brain health. The claim was bogus.

3) Don’t assume your doctor’s recommendation is the ideal prenatal supplement. A recent study (LG Saldanha et al, Journal of the American Academy of Dietetics, 117: 1429-1436, 2017) compared prescription (the kind your doctor is likely to prescribe) and non-prescription prenatal supplements. It found:

Compared with non-prescription supplements, prescription supplements contained significantly fewer vitamins (9 versus 11) and minerals (4 versus 8).

While prescription supplements contained more folic acid than non-prescription supplements, they contained significantly less vitamin A, vitamin D, iodine, and calcium.

4) Look for a prenatal supplement containing all the essential nutrients, not just those important for a healthy pregnancy. The authors of the first study made the point that most women will stop taking their regular multivitamin when they start their prenatal supplement. If that is you, your prenatal supplement should contain the nutrients you were getting from your multivitamin.

5) Look for a prenatal supplement that provide 100% of DV for all nutrients except the bulky ones. The ideal prenatal supplement should contain 100% of the DV for pregnant and lactating women for all essential nutrients. Avoid supplements with very low amounts of some nutrients and large excesses of others.

Bulky nutrients like calcium, magnesium, and choline are exceptions. It would be hard to get 100% DV for those nutrients in any supplement you could swallow.

6) Look for a prenatal supplement that “fills the gap” for bulky nutrients.

Fortunately, the NIH has estimated how much of these nutrients the average American woman gets in her diet. That allows us to estimate how much the average woman needs to get from her prenatal supplement to bring her total intake up to the DV for pregnant and lactating women. That amounts to 458 mg for calcium, 166 mg for magnesium, and 272 mg for choline.

- That gives you a reasonable benchmark for assessing whether a prenatal supplement is providing enough of those important nutrients. When you read their labels, you will find most prenatal supplements are woefully inadequate for these nutrients.

- You also need to ask whether your diet is “average”. For example, the average American gets 72% of their calcium from dairy foods. If you do not consume dairy, you may need to get more calcium from your supplement.

7) Avoid the excesses. Your unborn baby is precious. You don’t want to expose it to potentially toxic doses of vitamins or minerals. Avoid any prenatal supplement containing thousands of percent of the DV for some nutrients. And I would recommend caution with supplements containing over 200% of the DV for some nutrients if you are taking other supplements that may provide the same nutrient(s).

The Bottom Line

Two recent studies have surveyed hundreds of prenatal vitamins and asked whether they provided adequate amounts of the nutrients that are essential for a healthy pregnancy. The results were shocking.

While most prenatal supplements provided adequate amounts of folic acid, vitamin B12, vitamin B6, vitamin D, and iron…

They were woefully inadequate for vitamin K, calcium, choline, iodine, and DHA – all nutrients that are essential for a healthy pregnancy.

Furthermore, prescription prenatal supplements (the kind your doctor is likely to prescribe) were no better than non-prescription supplements.

The authors of the first study concluded, “[Our] analysis found that prenatal supplements vary widely in content, often only contain a subset of essential vitamins, and the levels were often below…recommendations.”

In other words, their study found that most prenatal vitamins on the market may not be adequate to support your needs and the needs of your child through pregnancy and breastfeeding.

For more details on this study and my discussion of how you can select the ideal prenatal supplement for you and your unborn child, 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