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Which Nutrients Prevent Prenatal Depression?

May 14, 2024 by Dr. Steve Chaney

What Does This Study Mean For You?

Author: Dr. Stephen Chaney

Yes, you read the headline correctly. Everyone talks about postnatal depression. But prenatal depression is also a “thing”, especially during the third trimester.

Worldwide, 4-20% of women experience some degree of depression during the third trimester – with pregnant women in high-income countries at the lower end (4-10%) of depression risk.
In contrast, the incidence of postnatal depression is 10-15%.

It is probably no coincidence that the incidence of depression is greatest during the third trimester and during the postnatal period.

The third trimester is the most difficult part of pregnancy for many women.
When a woman brings her baby home from the hospital her orderly life becomes chaotic.

But what role does nutrition play?

While not definitive, many studies suggest that supplementation with B vitamins, especially folic acid, B6, and B12; omega-3 fatty acids; vitamin D; and iron reduce the risk of postnatal depression.
However, there is much less information on which nutrients reduce the risk of prenatal depression.

Based on studies suggesting both iron and vitamin D deficiencies may negatively impact mental health, the authors of this study (JL Evanchuk et al, The Journal Of Nutrition. 154, 174-184, 2024) set out to determine whether iron and/or vitamin D deficiencies increase the risk of prenatal depression during the first trimester.

How Was This Study Done?

The authors recruited 2189 newly pregnant mothers from Calgary and Edmonton in Ontario Canada between 2009 and 2012. Participants in the study visited clinics in the area upon entry into the study; midway through the first, second, and third trimesters; and at multiple timepoints up to 3 months during the postpartum period.

In addition to the usual pregnancy wellness tests, participants filled out a 24-hour dietary recall and a Supplemental Intake Questionnaire to determine intakes of iron and vitamin D.

Note: The participants were all advised to take some form of prenatal supplement during the study. That’s because prenatal supplements are considered “the standard of care” for pregnant woman, so it would be considered unethical not to include a prenatal supplement in this study.

At the mid-point of the second trimester blood samples were drawn and analyzed for biomarkers of iron and vitamin D insufficiency. For iron the biomarkers were serum ferritin, soluble transferrin receptor, and hepcidin. For vitamin D, the biomarkers were 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and 3-epi-25-hydroxyvitamin D.

Iron deficiency was defined as serum ferritin levels <15 µg/L. Vitamin D insufficiency was defined as 25-hydroxyvitamin D levels < 75nmol/L. The other biomarkers were used to confirm these diagnoses.

Maternal depression was measured midway through the third trimester and ~3 months postpartum using 10-item questionnaire called the Edinburg Postnatal Depression Scale (EPDS). The EPDS ranks depression on a scale of 0 to 30, with a score of ≥13 considered an indication of likely depression.

The characteristics of the women enrolled in this study were:

Average age = 31.5
Average prepregnancy BMI = 23 (healthy weight).
Married or cohabitating with a partner = 97%.
Highly educated (college or postgraduate degree) = 68%.
Income above $70,000/year = 78%.
First child = 54%.
White = 80%.

Based on the Edinburg Depression Scale, probably depression for the 1822 women who completed the study was 5.6% during the third trimester and 4.4% 3 months postpartum.

Note: The low incidence of depression seen in this study was probably due to:

The women in this study were of high socioeconomic status and were receiving excellent healthcare.

The women in this study were taking prenatal supplements that provided both iron and vitamin D.

Which Nutrients Prevent Prenatal Depression?

As I mentioned when describing how the study was designed, all participants in this study were advised to take a prenatal supplement. Consequently:

94% of the women in this study were taking a supplement containing iron with an average supplemental iron intake of 26 mg/day.

- Note: The RDA for iron during pregnancy is 30 mg/day and most prenatal supplements provide 27 mg/day.

68% of the women in this study were taking a supplement containing vitamin D, with an average supplemental vitamin D intake of 330 IU/day.

- Note: The RDA for vitamin D during pregnancy is 600 IU/day, but most prenatal supplements provide far less than that.

When the investigators looked at iron and vitamin D status during the second trimester:

63.3% of the women had adequate levels of both iron and vitamin D.

14.8% of the women were low in vitamin D but had adequate iron levels.

18.4% of the women were low in iron but had adequate levels of vitamin D.

3.5% of the women were low in both iron and vitamin D.

RDAs are supposed to be enough to meet the nutrient requirements of 97-98% of healthy individuals, so it is perhaps surprising to see so many women with insufficient levels of iron (21.9%) and/or vitamin D (18.3%) in this study. This could be due to:

Insufficient intake.

- This is a likely explanation for vitamin D because the supplements women were using in this study provided around half the recommended RDA for vitamin D and the women lived at a northern latitude where sun exposure makes a small contribution to vitamin D levels.

- However, this is a less likely explanation for insufficient iron levels because the supplements provided 87% of the RDA for iron.

Inadequate RDAs. Studies like this one provide a rigorous test for the adequacy of existing RDAs. This study suggests the existing RDA for iron is adequate to meet the needs of ~80% of pregnant women, which is reassuring. However, it may need to be increased to reach the goal of meeting the iron requirements for 97-98% of pregnant women.

But the important question is whether the iron and vitamin D insufficiencies seen in this study mattered. The data suggested that they did.

For pregnant women with low iron, but adequate vitamin D levels in the second trimester, there was a small, but significant, increased risk of experiencing depression symptoms in the third trimester.

For pregnant women with low iron and vitamin D levels in the second trimester, the risk of experiencing depression symptoms in the third trimester increased by 2.2 points in the 30-point Edinburg Depression Scale.

- This is equivalent to a 7.4% increased risk of depression from deficiencies of iron and vitamin D alone – and these are only 2 of at least 8 nutrients thought to be associated with maternal depression.

The authors concluded, “Maternal iron and vitamin D biomarkers, measured during midpregnancy, were independently associated with third trimester maternal depression symptoms…This investigation is one of the first to report on the combined adequacy of maternal iron and vitamin D status during pregnancy and its impact on maternal depression.

The novelty of this work reinforces the need to ask similar questions [with other nutrients and] in other pregnant populations. Future investigations should report on the status of multiple nutrients and explore their independent and combined impact on health outcomes of pregnant individuals and their children.”

What Does This Study Mean For You?

Depression during pregnancy is bad for you. And because your fetus can sense your mood, it is bad for your baby. So, what should you do?

You can consult with your doctor about which antidepressants are safe to take during pregnancy. But the truth is there are no good choices. There are some antidepressants that are off limits. There are other antidepressants that appear to have little short-term risks, but we have no idea if there are long-term risks for your child.

So, what about natural approaches? Let’s start with nutrition.

The biggest takeaway from this study is that prenatal supplements may not be sufficient to prevent nutritional deficiencies that may cause prenatal depression for pregnant women.

This does not mean that every pregnant woman suffering prenatal depression should increase their iron and vitamin D levels.

However, if you are experiencing prenatal depression, you might want to ask your doctor about checking your iron and vitamin D status to determine if extra iron and/or vitamin D would be beneficial.

And to put this study into its proper perspective we need to remember that iron and vitamin D deficiencies are only two of many nutrients that may increase the risk of prenatal depression.

For example, in addition to iron and vitamin D, prenatal depression is associated with deficiencies of:

B vitamins, especially folate, B6 and B12. Most prenatal supplements provide the recommended RDA of folate for pregnant women, but not all contain RDA amounts of B6 and B12.

Calcium and magnesium. Very few prenatal supplements provide the recommended RDA for calcium and magnesium.

Omega-3s, especially DHA. Very few prenatal supplements provide DHA, and the few that do usually provide inadequate amounts of DHA.

So, when you are having your nutrition conversation with your doctor, you might not want to limit your conversation to iron and vitamin D.

Alternately, as I suggested last week’s issue of “Health Tips From the Professor”, you might wish to add a multivitamin supplement and an omega-3 supplement providing at least 300 mg of DHA plus EPA. This simple step would be sufficient to assure you have adequate levels of nutrients thought to be important for reducing the risk of prenatal depression.

And, of course, there are other lifestyle factors, as well. For example:

Diets high in highly processed foods are known to increase the risk of depression. And whole food, primarily plant-based diets decrease the risk of depression.

Overweight and obesity increase the risk of depression.

Regular exercise decreases the risk of depression.

The Bottom Line

A recent study looked at whether taking a prenatal supplement was sufficient to eliminate deficiencies of iron and vitamin D during pregnancy and whether deficiencies of these two nutrients during the second trimester of pregnancy increased the risk of depression during the third trimester.

When the investigators looked at iron and vitamin D status during the second trimester:

14.8% of the women were low in vitamin D but had adequate iron levels.

18.4% of the women were low in iron but had adequate levels of vitamin D.

3.5% of the women were low in both iron and vitamin D.

But the important question is whether the iron and vitamin D insufficiencies seen in this study mattered. The data suggested that they did.

For pregnant women with low iron, but adequate vitamin D levels in the second trimester, there was a small, but significant, increased risk of experiencing depression symptoms in the third trimester.

For pregnant women with low iron and vitamin D levels in the second trimester, the risk of experiencing depression symptoms in the third trimester increased by 2.2 points in the 30-point Edinburg Depression Scale.

This is equivalent to a 7.4% increased risk of depression from deficiencies of iron and vitamin D alone.

When you consider that iron and vitamin D are just two of 8 or more nutrients thought to be important for preventing depression during pregnancy, the question becomes what you can do to decrease your risk of developing depression during pregnancy and after the birth of your child.

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

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

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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.

What Nutrients Are Missing In Prenatal Supplements?

May 7, 2024 by Dr. Steve Chaney

Do These Deficiencies Matter?

Author: Dr. Stephen Chaney

If you are a pregnant mom, nothing is more important than the health of your baby. And if you are pregnant or thinking of becoming pregnant, your doctor has probably recommended a prenatal supplement. But does the prenatal supplement he or she recommended provide you with all the nutrients you need?

In a previous issue of “Health Tips From the Professor” I shared two studies that suggested the answer is, “No”. Those studies concluded that most prenatal supplements had little or no vitamin K, choline, DHA, and iodine – all of which are essential for the health of your newborn baby. And while most prenatal supplements contained calcium, the amount they provided was far below recommended levels.

The authors of the first study also made the point that most women going on a prenatal supplement will probably discontinue taking their multivitamin supplement, so a good prenatal supplement should provide all the essential nutrients.

But they don’t. Folic acid, iron, calcium, and vitamin D have long been recognized as essential for a healthy pregnancy. So, virtually every prenatal supplement contained these four nutrients, although calcium is often present in suboptimal amounts. Beyond those four nutrients, the design of prenatal supplements is haphazard. Some contain vitamin K, choline, iodine, or DHA (often in suboptimal amounts). But almost none contain all four nutrients.

And when you consider the other essential nutrients you find in most multivitamins, prenatal supplements often come up empty. Is that a problem? That’s what this study (KM Godfrey et al, PLOS Medicine, 1-27, December 5, 2023) was designed to find out.

How Was This Study Done?

This was a double-blind, placebo-controlled clinical trial, the gold standard for clinical studies. The investigators recruited 1,729 women who were planning to get pregnant from England, Singapore, and New Zealand between 2015 and 2017.

The women were randomly split into two groups:

The control group received a supplement containing nutrients that were most frequently included in prenatal supplements in those countries (folic acid, iron, calcium, iodine, and beta-carotene).

The intervention group received a supplement containing those nutrients plus riboflavin, vitamin B6, vitamin B12, vitamin D, zinc, inositol, and probiotics).

Riboflavin, vitamin B6, vitamin B12, vitamin D, and zinc were included because they are included in most multivitamins but are often missing in prenatal supplements.

Inositol was included because some studies have suggested that inositol may reduce the risk of maternal hyperglycemia and gestational diabetes.

Blood samples to assess nutritional status were obtained from all women in the study before the trial started (baseline) and after 1 month of supplementation with either the control or intervention formulation.

Of the women entering the study, 512 went on to have a singleton (one child) pregnancy. For these women supplementation was continued until childbirth. Additional blood samples were obtained in early and late pregnancy and at 6 months postdelivery. [Note: no supplementation was provided to either group postdelivery. And this is also a period of time when most women would be breastfeeding.]

The blood samples were tested for:

Blood levels of folic acid, riboflavin, vitamin B6, vitamin B12, and vitamin D.

Functional biomarkers of deficiencies of each of these vitamins.

What Nutrients Are Missing In Prenatal Supplements?

There was no difference in maternal hyperglycemia or gestational diabetes between the control group and the intervention group supplemented with inositol, so I will focus on the other nutrients present in the intervention group.

At baseline when subjects were first entered into the study.

29.2% of the subjects had low or marginal status for folic acid.

82.0% of the subjects had low or marginal status for riboflavin.

1.3% of the subjects had low or marginal status for vitamin B6.

9.1% of the subjects had low or marginal status for vitamin B12.

48.7% of the subjects had low or marginal status for vitamin D.

91.0% of the subjects had low or marginal status for one or more of these vitamins.

In the control group receiving folic acid but no riboflavin, vitaminB6, vitamin B12, and vitamin D:

Folic acid deficiency fell to 4.1% after 1 month of supplementation (the supplement used by the control group contained folic acid), 1% in early pregnancy, 6.1% in late pregnancy, and rose to 31.8% 6 months after supplementation was discontinued. The intervention group got the same amount of folic acid, and their results were similar.

Riboflavin deficiency ranged from 82-92% during pregnancy and returned to 82% 6 months postdelivery.

Vitamin B6 deficiency increased to 54% in late pregnancy and returned to 1.2% 6 months postdelivery.

Vitamin B12 deficiency increased to 55% in late pregnancy and returned to 12.4% 6 months postdelivery.

Vitamin D deficiency ranged from 35-43% during pregnancy and returned to 31% 6 months postdelivery.

Functional markers of vitamin B6 deficiency were evident by late pregnancy.

In short, data from the control group fell into 3 categories:

The data with folic acid confirm previous studies showing that folic acid in the amount present in most prenatal supplements is effective at preventing folic acid deficiency before and during pregnancy. It also strengthens the argument for continuing folic acid supplementation during breastfeeding.

Deficiencies of riboflavin and vitamin D are prevalent in women of childbearing age, but pregnancy does not appear to significantly impact the percentage of women who are deficient in these nutrients.

Deficiencies of vitamins B6 and B12 are rare in women of childbearing age, but pregnancy significantly depletes both nutrients.

- This was particularly evident for vitamin B6. Blood levels of vitamin B6 markers decreased to a level that could impact the functioning of vitamin B6-depended metabolic pathways.

For the intervention group receiving additional riboflavin, vitamin B6, vitamin B12, and vitamin D:

Deficiencies of these vitamins were eliminated by one month of supplementation.

Vitamin levels remained adequate during pregnancy.

Except for vitamin B12, deficiencies of these vitamins reappeared when supplementation was discontinued for 6 months. The maintenance of adequate B12 levels 6 months after supplementation stopped was expected because the body holds on to its B12 stores very tightly.

In short deficiencies of these nutrients before and during pregnancy could be eliminated by supplementation with levels of these nutrients found in many multivitamins.

The authors concluded, “Over 90% of the trial participants had low concentrations of one or more of folate, riboflavin, vitamin B12, or vitamin D during preconception, and many developed markers of vitamin B6 deficiency in late pregnancy. Preconception/pregnancy supplementation in amounts available in over-the-counter supplements substantially reduces the prevalence of vitamin deficiency and depletion markers before and during pregnancy, with higher maternal plasma vitamin B12 maintained during the recommended lactation period.”

Do These Deficiencies Matter?

It is well established that deficiencies of folic acid and vitamin D cause health risks for the mother and developmental risks for the fetus, so I won’t discuss these nutrients here.

However, the effect of riboflavin, vitamin B6, and vitamin B12 deficiencies on pregnancy is less well known, which is probably why these nutrients are often not added to prenatal supplements.

The authors of the study said small studies have suggested that:

Low or deficient riboflavin status may be associated with a higher risk of anemia during pregnancy.

Low vitamin B6 status may be associated with an increased risk of preterm birth and development of metabolic health risks in the child.

Low vitamin B12 status may be associated with increased risk of gestational diabetes and pre-eclampsia in the mother, and increased risk of neural tube defects, preterm birth, low birth weight, and neurocognitive delays in the baby – with the strongest evidence being an effect on neurocognitive development.

While none of these risks have been definitively proven, the authors point out that deficiencies of these nutrients can easily be eliminated with inexpensive, over-the-counter multivitamin supplements.

What Does This Study Mean For You?

Perhaps I should start this section by asking why these deficiencies are so common in women of child-bearing age.

The authors speculate that part of the reason is that many women are giving up meat (B12 and iron) and dairy (calcium and riboflavin) for health or environmental reasons.

However, they also point out that a more likely cause is that more than 60% of calories consumed in countries like England, New Zealand, and the United States comes from ultra-processed foods – otherwise known as “empty calories”.

Whatever the cause, the authors conclude, “…the findings suggest a need to reappraise dietary recommendations for preconception and pregnancy to consider further the role of multiple micronutrient supplements for women living in higher-income countries.” I agree.

In a previous “Health Tips From the Professor” article, I reported a recent study showing that most prenatal supplements have either no or inadequate amounts of vitamin K, choline, DHA, iodine, and calcium, nutrients that are absolutely essential for a healthy pregnancy. And I gave recommendations for choosing the best prenatal supplement for you and your child.

That study also noted that many women discontinue their multivitamin supplement when they start taking a prenatal supplement. The current study indicates that practice may be unwise. It shows that:

Many women of childbearing age are deficient in one or more of these essential nutrients, and…

Essential nutrients not found in most prenatal supplements may also be important for a healthy pregnancy.

So, if you are pregnant or thinking of becoming pregnant, follow this article’s recommendation to start with a well-designed prenatal supplement that provides adequate amounts of folate, iron, calcium, vitamin D, vitamin K, choline, DHA, and iodine and add a multivitamin supplement that provides the other essential nutrients. Alternatively, a simpler approach would be to choose a well-designed prenatal supplement that includes all the essential nutrients. That would be my recommendation.

I would also note this study showed that deficiencies of most of these nutrients reappeared as soon as supplementation was discontinued. Although the authors of this study did not mention it, this reinforces the importance of continuing supplementation during breastfeeding.

The Bottom Line

I have previously reported on a study that concluded many prenatal supplements lack one or more nutrients shown to be important for a healthy pregnancy. But let’s say you have found a prenatal supplement that provides all those nutrients. Is that enough?

Studies show that most women stop taking their multivitamin supplement when they start on a prenatal supplement. But is that a good idea? Are there essential nutrients found in multivitamins, but not in many prenatal supplements that are also important for a healthy pregnancy?

A recent study asked that question in women who were trying to become pregnant. The study found that:

Many women of childbearing age are deficient in one or more essential nutrients found in multivitamin supplements but often missing in prenatal supplements, and…

Essential nutrients not found in most prenatal supplements may also be important for a healthy pregnancy.

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

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

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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

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.

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