Is Your Prenatal Supplement Adequate?

What Should You Look For In A Prenatal Supplement?

Author: Dr. Stephen Chaney

pregnant women taking omega-3You 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?

clinical studyThis 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:

  1. 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?

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

  1. 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:

calcium supplementsThis 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?

Questioning WomanBy 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.

  1. 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

 

How Much Omega-3 Should You Take During Pregnancy?

Which Omega-3s Are Beneficial? 

Author: Dr. Stephen Chaney

Premature BabyPreterm births (births occurring before 37 weeks) are increasing in this country. Just between 2018 and 2019, the percentage of preterm births increased by 2% to over 10% of all pregnancies. That is a concern because preterm births are associated with an increased risk of:

  • Visual impairment.
  • Developmental delays.
  • Learning difficulties.
  • Problems with normal development of lungs, eyes, and other organs.

Plus, it is expensive to keep premature babies alive. One recent study estimated that reducing the incidence of preterm births by around 50% could reduce health care costs by $6 billion in the United Stated alone.

Of the 10% preterm births, 2.75% of them are early preterm births (births occurring before 34 weeks). Obviously, the risk of health problems and the cost of keeping them alive is greatest for early preterm babies.

We don’t know why preterm births are increasing, but some experts feel it is because in this country:

  • More older women are having babies.
  • There is increased use of fertility drugs, resulting in multiple babies

Unfortunately, there is no medical standard for identifying pregnancies at risk for preterm birth. Nor is there any agreement around prevention measures for preterm births.

However, recent research has suggested that some premature births may be caused by inadequate omega-3 status in the mother and can be prevented by omega-3 supplementation.

What Do We Know About Omega-3s And Risk Of Preterm Births?

omega-3s during pregnancy is healthyThe role of omega-3s on a healthy pregnancy has been in the news for some time. Claims have been made that omega-3s reduce preterm births, postnatal depression, and improve cognition, IQ, vision, mental focus, language, and behavior in the newborn as they grow.

The problem is that almost all these claims have been called into question by other studies. If you are pregnant or thinking of becoming pregnant, you don’t know what to believe.

Fortunately, a group called the Cochrane Collaboration has recently reviewed these studies. The Cochrane Collaboration consists of 30,000 volunteer scientific experts from across the globe whose sole mission is to analyze the scientific literature and publish reviews of health claims so that health professionals, patients, and policy makers can make evidence-based choices about health interventions. Their reviews are considered the gold standard of evidence-based medicine.

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

The problem is the authors of most meta-analyses group studies together without considering the quality of studies included in their analysis. This creates a “Garbage In – Garbage Out” effect. If the quality of individual studies is low, the quality of the meta-analysis will also be low.

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

For omega-3s and pregnancy, the Cochrane Collaboration performed a meta-analysis and review of 70 randomized controlled trials that compared the effect of added omega-3s on pregnancy outcomes with the effect of either a placebo or no omega-3s. These trials included almost 19,927 pregnant women.

This Cochrane Collaboration Review looked at all the claims for omega-3s and pregnancy outcome, but they concluded that only two of the claims were supported by high-quality evidence:

  • Omega-3s reduce the risk of preterm births.
  • Omega-3s reduce the risk of low birth-weight infants.

The authors concluded: “Omega-3 supplementation during pregnancy is an effective strategy for reducing the riskclinically proven of preterm birth…More studies comparing [the effect of] omega-3s and placebo [on preterm births] are not needed at this point.”

In other words, they are saying this conclusion is definite. The Cochrane Collaboration has declared that omega-3 supplementation should become part of the standard of medical care for pregnant women.

However, the Cochrane Collaboration did say that further studies were needed “…to establish if, and how, outcomes vary by different types of omega-3s, timing [stage of pregnancy], doses [of omega-3s], or by characteristics of women.”

That’s because these variables were not analyzed in this study. The study included clinical trials:

  • Of women at low, moderate, and high risk of poor pregnancy outcomes.
  • With DHA alone, with EPA alone, and with a mixture of both.
  • Omega-3 doses that were low (˂ 500 mg/day), moderate (500-1,000 mg/day), and high (> 1,000 mg/day).

I have discussed these findings in more detail in a previous issue of “Health Tips From The Professor”

How Was This Study Done?

Clinical StudyThe current study (SE Carlson et al, EClinicalMedicine, 2021) is a first step towards answering those questions.

The authors of this study focused on how much DHA supplementation is optimal during pregnancy. This is an important question because there is currently great uncertainty about how much DHA is optimal:

  • The American College of Obstetrics and Gynecology recommends supplementation with 200 mg/day of DHA. However, that recommendation assumes that the increase will come from fish and was influenced by concerns that omega-3-rich fish are highly contaminated with heavy metals and PCBs.
  • Another group of experts was recently asked to develop guidelines for omega-3 supplementation during pregnancy. They recommended pregnant women consume at least 300 mg/day of DHA and 220 mg/day of EPA.
  • The WHO has recommended of minimum dose of 1,000 mg of DHA during pregnancy.
  • Many prenatal supplements now contain 200 mg of DHA, but very few provide more than 200 mg.

Accordingly, the authors took the highest and lowest recommendations for DHA supplementation and asked whether 1,000 mg of DHA per day was more effective than 200 mg of DHA at reducing the risk of early preterm births. Their hypothesis was that 1,000 mg of DHA would be more effective than 200 mg/day at preventing early preterm births.

This study was a multicenter, double-blind, randomized trial of 1032 women recruited at one of three large academic medical centers in the United States (University of Kansa, Ohio State University, and University of Cincinnati).

  • The women were ≥ 18 years old (average age = 30) and between 12 and 20 weeks of gestation when they entered the study.
  • The breakdown by ethnicity was 50% White, 22% Black or African American, 22% Hispanic, 6% Other.
  • 18% had a prior preterm birth (<37 weeks) and 7% had a prior early preterm birth (<34 weeks).
  • Prior to enrollment in the study 47% of the participants reported taking a DHA supplement and 19% of the participants took a DHA supplement with > 200 mg/day.

All the participants received 200 mg DHA capsules and were told to take one capsule daily. The participants were also randomly assigned to take 2 additional capsules that contained a mixture of corn and soybean oil (the 200 mg DHA/day group) or 2 capsules that contained 400 mg of DHA (the 1,000 mg DHA/day group). The capsules were orange flavored so the participants could not distinguish between the DHA capsules and the placebo capsules.

Blood samples were drawn upon entry to the study and either just prior to delivery or the day after delivery to determine maternal DHA status.

The study was designed to look at the effect of DHA dose (1,000 mg or 200 mg) on early preterm birth (<34 weeks), preterm birth (<37 weeks), low birth weight (< 3 pounds), and several other parameters related to maternal and neonatal health.

How Much Omega-3 Should You Take During Pregnancy?

pregnant women taking omega-3The primary findings from this study were:

  • The rate of early preterm births (<34 weeks) was less (1.7%) for pregnant women taking 1,000 mg of DHA/day compared to 200 mg/day (2.4%).
  • The rate of late preterm births (between 34 and 37 weeks) was also less for women taking 1,000 mg of DHA/day compared to 200 mg/day.
  • Finally, low birth weight and the frequency of several maternal and neonatal complications during pregnancy, delivery, and immediately after delivery were also lower with 1,000 mg/day of supplemental DHA than with 200 mg/day.

This confirms the authors’ hypothesis that supplementation with 1,000 mg/day of DHA is more effective than 200 mg/day at reducing the risk of early preterm births. In addition, this study showed that supplementation with 1,000 mg of DHA/day had additional benefits.

This study did not have a control group receiving no DHA. However:

  • The US average for early preterm births is 2.74%.
  • For the women in this study who had previous pregnancies, the rate of early preterm birth was 7%.

Of course, the important question for any study of this type is whether all the women benefited equally from supplementation. Fortunately, this study was designed to answer that question.

As noted above, each woman was asked whether they took any DHA supplements at the time they enrolled in the study, and 47% of the women in the study were taking DHA supplements when they enrolled. In addition, the DHA status of each participant was determined from blood samples taken at the time the women were enrolled in the study. When the authors split the women into groups based on their DHA status at the beginning of the study:

  • For women with low DHA status the rate of early preterm births was 2.0% at 1,000 mg of DHA/day versus 4.1% at 200 mg of DHA/day.
  • For women with high DHA status the rate of early preterm births was around 1% for both 1,000 mg of DHA/day and 200 mg of DHA/day.

In other words, DHA supplementation only appeared to help women with low DHA status. This is good news because:

  • DHA status is an easy to measure predictor of women who are at increased risk of early preterm birth.
  • This study shows that supplementation with 1,000 mg of DHA/day is effective at reducing the risk of early premature birth for women who are DHA deficient.

In the words of the authors, “Clinicians could consider prescribing 1,000 mg DHA daily during pregnancy to reduce early preterm birth in women with low DHA status if they are able to screen for DHA.”

Which Omega-3s Are Beneficial?

DHA is the most frequently recommended omega-3 supplement during pregnancy.

It is not difficult to understand why that is.

  • DHA is a major component of the myelin sheath that coats every neuron in the brain. [You can think of the myelin sheath as analogous to the plastic coating on a copper wire that allows it to transmit electricity from one end of the wire to the other.]
  • Unlike other components of the myelin sheath, the body cannot make DHA. It must be provided by the diet.
  • During the third trimester, DHA accumulates in the human brain faster than any other fatty acid.
  • Animal studies show that DHA deficiency during pregnancy interferes with normal brain and eye development.
  • Some, but not all, human clinical trials show that DHA supplementation during pregnancy improves developmental and cognitive outcomes in the newborn.
  • Recent studies have shown that most women in the United States only get 60-90 mg/day of DHA in their diet.

Clearly, DHA is important for fetal brain development during pregnancy, and most pregnant women are not getting enough DHA in their diet. This is why most experts recommend supplementation with DHA during pregnancy. And this study suggests supplementation with 1,000 mg/day is better than 200 mg/day. However, two important questions remain:Questioning Woman

#1: Is 1,000 mg of DHA/day optimal? The answer is, “We don’t know”. This study compared the highest recommended dose (1,000 mg/day) with the lowest recommended dose (200mg/day) and concluded that 1,000 mg/day was better than 200 mg/day.

But would 500 or 800 mg/day be just as good as 1,000 mg/day? We don’t know. More studies are needed.

#2: Can DHA do it all, or are other omega-3s also important for a healthy pregnancy? As noted above, the emphasis on supplementation with DHA was based on the evidence for a role of DHA in fetal brain development during pregnancy.

But is DHA or EPA more effective at preventing early preterm birth and maternal pregnancy complications? Again, we don’t know.

As noted above, the Cochrane Collaboration concluded that omega-3s were effective at reducing early preterm births but was unable to evaluate the relative effectiveness of EPA and DHA because their review included studies with DHA only, EPA only, and EPA + DHA.

This is an important question because the ability of the body to convert EPA to DHA and vice versa is limited (in the 10-20%) range. This means that if both EPA and DHA are important for a healthy pregnancy, it might not be optimal to supplement with a pure DHA or pure EPA supplement.

Based on currently available data if you are pregnant or thinking of becoming pregnant, my  recommendations are:

  • Chose a supplement that provides both EPA and DHA.
  • Because the evidence is strongest for DHA at this time, chose an algal source of omega-3s that has more DHA than EPA.
  • Aim for a dose of DHA in the 500 mg/day to 1,000 mg/day range. Remember, this study showed 1,000 mg/day was better than 200 mg/day but did not test whether 500 or 800 mg/day might have been just as good.

As more data become available, I will update my recommendations.

The Bottom Line

The Cochrane Collaboration recently released a report saying that the evidence was definitive that omega-3 supplementation during pregnancy reduced the risk of early preterm births. However, they were not able to reach a definitive conclusion on the optimal dose of omega-3s or the relative importance of EPA and DHA at preventing early preterm birth.

Most experts recommend that pregnant women supplement with between 200 mg/day and 1,000 mg/day of DHA.

A recent study asked whether 1,000 mg of DHA/day was better than 200 mg/day at reducing the risk of early preterm birth. The study found:

  • The rate of early preterm births (<34 weeks) was less (1.7%) for pregnant women taking 1,000 mg of DHA/day than pregnant women taking 200 mg/day (2.4%).
  • For women with low DHA status at the beginning of the study, the rate of early preterm births was 2.0% at 1,000 mg of DHA/day versus 4.1% at 200 mg of DHA/day.
  • For women with high DHA status at the beginning of the study, the rate of early preterm births was around 1% for both 1,000 mg of DHA/day and 200 mg of DHA/day.

The authors concluded, “Clinicians could consider prescribing 1,000 mg DHA daily during pregnancy to reduce early preterm birth in women with low DHA status…”

There are two important caveats:

  • This study did not establish the optimal dose of DHA. The study concluded that 1,000 mg/day was better than 200 mg/day. But would 500 or 800 mg/day be just as good as 1,000 mg/day? We don’t know. More studies are needed.
  • This study did not establish the relative importance of EPA and DHA for reducing the risk of early preterm births. DHA is recommended for pregnant women based on its importance for fetal brain development. But is DHA more important than EPA for reducing the risk of early preterm births? Again, we don’t know. More studies are needed.

For more details about 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.

Prenatal DHA Supplement

Author: Dr. Stephen Chaney

Is taking a prenatal DHA supplement wise for brain health?

There are lots of reasons to think that DHA supplementation may be important for healthy brain development.

  • DHA is a major component of the myelin sheath that coats every neuron in the brain.
  • Just as the plastic coating on copper wire allows it to conduct an electrical current, the myelin sheath allows neurons to conduct nerve impulses from one end of the neuron to the other. In short, the myelin sheath is absolutely essential for brain function.
  • Unlike many of the other components of the myelin sheath, the body cannot make DHA. It must be provided by the diet.
  • Recent studies have suggested that most women in the United States and Canada do not get sufficient amounts of the omega-3s EPA and DHA in their diet.
  • Animal studies show that DHA deficiency during pregnancy interferes with normal brain and eye development.

With all that circumstantial evidence, it would seem obvious that a prenatal DHA supplement would be important for healthy brain development in infants and children.  However, clinical studies have been all over the map.

Some studies have reported that DHA supplementation during pregnancy improves cognition, attention span, behavior or reading skills in both infants and children.  Other studies have shown no effect of DHA supplementation on those parameters.  There is no consensus on this very important question.

Thus, when I saw a recent study titled “Prenatal Supplementation with DHA Improves Attention At 5 Years Of Age: A Randomized Controlled Trial” (U Ramakrishnan et al, American Journal of Clinical Nutrition, doi: 10.3945/ajcn.114.101071, 2016), I decided to Investigate.

 

Does Taking a Prenatal DHA Supplement Improve Attention Span?

healthy brains for kidsIn this study 1094 Mexican women were randomly assigned to receive either 400 mg of DHA or a placebo containing corn and soy oil starting in the second trimester of pregnancy (a time at which myelination and brain development begins) until delivery. Of the women enrolled in the study, 973 of them gave birth to healthy babies.

The investigators were able to follow up with 797 (82%) of those children at age 5 and conducted tests to measure overall cognitive function, behavior, and attention span.

  • There were no differences in overall cognitive development or behavior between the two groups.
  • The children from mothers who supplemented with DHA performed significantly better in tests of attention span. They were much less likely to be distracted by external stimuli than the children from mothers not supplementing with DHA.
  • In short, this study suggested that supplementation with DHA during pregnancy produced children who were less likely to suffer from attention deficit disorders at age 5.

This study had a number of strengths:

  • It was a fairly large study (797 children).
  • Supplementation was with pure DHA rather than with a mixture of EPA, DHA, and other omega-3 fatty acids.
  • The population was from an urban area of Mexico where omega-3 intake is generally low, so it was likely that many of the women were DHA-deficient at the beginning of the study.

However, it also had some glaring weaknesses:

  • The DHA status of the women was not measured either at baseline or after supplementation.
  • The quality of the child’s learning environment was not measured.

In short, the study was neither better or worse than the many other published studies.

 

Why Is There So Much Confusion?

To try and clear up the confusion I have also analyzed many of the other published studies in this field. There were things not to like about every study, but there was no obvious reason why some studies showed a positive effect of DHA supplementation and others failed to see any benefit. This is not unusual for human nutrition clinical studies, but it is frustrating.

However, when you look at the totality of the studies in this field there is one obvious reason why there is so much confusion. There is no uniformity in experimental design. No two studies are alike.

The published studies differ in:

  • The composition of omega-3s. Some studies are done with pure DHA. Others with mixtures of EPA and DHA and with varying ratios of EPA to DHA.
  • The amount of DHA. Studies range from 100 mg/day to 800 mg/day.
  • When the DHA is given. Some studies give the DHA to the pregnant mothers. Others give DHA to infants or to children of various ages.

Even worse, most of the published studies to date have not measured omega-3 status prior to supplementation, nor have they documented an improvement in omega-3 status with supplementation. Obviously, DHA supplementation is most likely to be beneficial for individuals who were DHA-deficient at the beginning of the study.

Until there is some uniformity in experimental design and DHA status is routinely measured, it is likely that the confusion will continue and this important question will remain unanswered.

 

  Should Pregnant Women Take a Prenatal DHA Supplement?

prenatal dha supplementIf we were to assume that most American women were getting enough omega-3s in their diet, and the consequences of DHA deficiency were relatively minor, this would be merely an academic discussion. We could afford to wait years until scientists were able to come to a consensus.

However, neither of those assumptions are true:

  • One recent study reported that the United States and Canada rated last in the world with respect to omega-3 intake.
  • If any of the reported consequences (short attention span, cognitive deficits, and behavioral problems) of DHA-deficiency during pregnancy and childhood are true and they are preventable with DHA supplementation, this information is of vital importance to every woman during her child bearing years.

In short, inadequate DHA intake is so widespread and the possible consequences of DHA deficiency during pregnancy are so important that, in my opinion, a prenatal DHA supplement only makes sense. Pregnant women can’t afford to wait until we are absolutely sure that DHA supplementation is essential.

The only caveat to this recommendation is to make sure that the DHA you are getting is pure. Our oceans are increasingly polluted. Many fish and some fish oil supplements are contaminated with heavy metals and/or PCBs. Only use omega-3 and/or DHA supplements from manufacturers that use very stringent quality controls to assure their products are pure.

 

The Bottom Line

 

  • A recent study has reported that DHA supplementation during pregnancy improves attention span in children at age 5.
  • Unfortunately, there is no consensus in this field. Some studies have come to similar conclusions while others have seen no effect of DHA supplementation during pregnancy.
  • If we were to assume that omega-3 deficiency was rare in this country and the consequences of DHA deficiency during pregnancy were inconsequential, this would be an academic discussion. Pregnant women could wait for scientists to reach consensus before deciding whether or not to supplement with DHA. However, neither of those studies are true.
  • Studies show that most women in the US and Canada do not get adequate omega-3s during pregnancy.
  • If any of the reported consequences of DHA deficiency during pregnancy are true and they are preventable with DHA supplementation, this information is of vital importance to every woman during her pregnancy.
  • In short, inadequate DHA intake is so widespread and the possible consequences of DHA deficiency during pregnancy are so important that, in my opinion, DHA supplementation during pregnancy only makes sense. Pregnant women can’t afford to wait until we are absolutely sure that DHA supplementation is essential.
  • The only caveat to this recommendation is to make sure that the DHA you are getting is pure. Our oceans are increasingly polluted. Many fish and some fish oil supplements are contaminated with heavy metals and/or PCBs. Only use omega-3 and/or DHA supplements from manufacturers that use very stringent quality controls to assure their products are pure.

 

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