Nutrition During Pregnancy and Lactation: Exploring New Evidence

Guest post by Cindy Turner-Maffei, MA, ALC, IBCLC

Cindy Turner-Maffei, MA, ALC, IBCLC at the academy.

Did you know that the Dietary Guidelines for America (DGA), now 40 years old, have never included guidance for nutrition during pregnancy, lactation, infancy or for children under age 2? Worrisome when you think about the lifelong impact of nutrition in these crucial formative time frames.

Congress mandated that the next edition of the DGA, due later this year, provide nutrition guidance for pregnancy, lactation, and through age 2 years.

At the end of January, I had the great honor and pleasure of attending Nutrition During Pregnancy and Lactation: Exploring New Evidence – A Workshop, a 2-day workshop at the National Academy of Sciences (NASEM) in Washington, DC.  The National Academies of Health and Medicine sponsored this workshop to “explore the current state of the science on nutrients, dietary patterns, nutritional supplements, and other nutrition-based topics relevant to pregnancy and lactation. The workshop topics will include discussion of equity in access to nutritional care for women of childbearing age.” The last in-depth compilation of knowledge about this crucial topic was published by the Institute of Medicine (now the National Academy of Medicine) in 1990!

Conference opening slide.

Backstory of this workshop: In developing the 2020 DGA, the 2020 Dietary Guidelines Advisory Committee (DGAC) has developed a list of questions about nutrition needs in this crucial timeframe, and has begun an evidence review. A new Ad Hoc Committee led by Dr. Kathryn Dewey was identified to explore the infancy questions. This January meeting is the DGAC bringing together  top notch researchers who could share cutting-edge information about the research to inform their knowledge on those questions. Attending 2 days of concise and information dense presentations beginning at 8 am and running through 5 pm, was kind of like sitting in on a high-level nutrition briefing, in a similar vein to the intense briefings I was sure were going on right across the street at the Department of State. It was definitely nutrition science brain gym for me!

In order to summarize my learning, and share that knowledge with all of you, I live-tweeted the event. Below are my tweets in chronological order. Next week we will share a summary of Day 2. NASEM has made the videos of the Nutrition during Pregnancy & Lactation available here.

January 29, 2020

Anna Maria Siega-Riz updated us about changes among new parents since the 1990 IOM reports on nutrition in pregnancy and lactation: birthing folk today are older, heavier, less likely to smoke, more likely to birth surgically, and more likely to be diabetic.

Alison Steiber of the Academy of Nutrition & Dietetics (AND) shared that AND has launched a study examining how dietitians work with breastfeeding families.

Maria Makrides of SAHMRI Women and Kids at South Australian Health and Medical Research Institute reported on research about docosahexaenoic acid (DHA – an omega-3 fatty acid) supplementation during pregnancy, finding no significant decrease in postpartum depression, and no impact on cognition in children. 

  • On the 2018 Cochrane review of impact of DHA supplementation in pregnancy, she states:  “preterm birth < 37 weeks and early preterm birth < 34 weeks were reduced in women receiving omega-3 (Ω-3) long-chain polyunsaturated fatty acids (LCPUFA).” However, the DOMInO trial does not support this finding. 
  • Paraphrasing Makrides: “Women who start pregnancy with low omega-3 levels are at risk of preterm birth; that risk is reduced by supplementation with Ω-.. We found no benefits related to preterm birth for supplementation of pregnant folk who are Ω-3 replete*.” (*replete refers to having adequate stores in the body)
  • “Our research also concluded that DHA supplementation in pregnancy does not significantly decrease risk of allergies and asthma in children at hereditary risk.”
  • Consumption of 8 to 12 ounces of wild caught fatty fish weekly should maintain appropriate Ω-3 levels. Farmed fish is less ideal. 
    • {CTM note: check out safe dietary Ω-3 sources for pregnancy consumption here and here.)


Dr. Elango

Rajavel Elango of University of British Columbia on protein needs in pregnancy and lactation: 

  • “Protein needs were developed based on the needs of males. DRIs (Dietary Reference Intates) for pregnancy are based on males.” (?!?)
  • Our research in British Columbia suggests that protein needs in pregnancy are higher than the DRIs.
  • When protein intake is too high (>25% of kcal), the risks for high weight gain and fetal death increase
  • While pregnancy increases protein needs, not all amino acid are needed at the same level. Some individuals following plant-based diets may need help on how to balance protein and amino acid needs. We need more research on vegan and vegetarian diets in pregnancy.
  • In a well-nourished mother, variety of plant-based foods is probably fine (some dairy is a good addition, as it includes many needed amino acids). In a poorly nourished woman, assessing and meeting protein and amino acid intake is more crucial.
  • My lab has not evaluated how body type (overweight, underweight, obesity) impacts protein needs. Our work is with women of normal weight.


Leanne Redman of Pennington Biomedical Research Center on carbohydrates and energy requirements in pregnancy and lactation: 

  • In pregnancy, carbohydrate need increases 35% to fuel the fetal brain. 
  • In lactation, carbohydrates need doubles over non-pregnancy need, as glucose is used to make lactose. 
  • All carbs are not the same. Surveys of pregnant North Americans suggest intake of carbs is too high and fiber too low.
  • The National Institutes of Health (NIH) recommends decreasing added sugars (<10% of daily calories) and increasing fiber (28 g/d) in pregnancy.


Yvonne Lamers of University of British Columbia on folate and Vitamin B-12 in pregnancy and lactation:

  • The neural tube closes at 3 weeks gestation, before many know they are pregnant. WHO recommends 400 micrograms daily starting preconceptually through 12 weeks gestation. Women with previous child with neural tube defects need more.  
  • 20% of American women do not have sufficient folate in their red blood cells. Insufficient blood levels of folate are higher in African-American women (~35%).
  • In an era of food fortification, are folate supplements still required for pregnant women? YES! For all women, as it is needed early in pregnancy, before many know they are pregnant.
  • Response from Lamers to a later question about folate supplementation for those with the MTHFR genetic variant: The original concern about this arose in Europe where there is no universal FA fortification and lower folate status. Due to universal folate fortification, we are folate replete in No. America. Thus no difference in folate status between these genotypes and risk of neural tube defects. Theoretically there should be no difference between 5methyltetrahydrofolate and other folate sources, but research is needed to assure us that it is absorbed in the same manner as other folate sources. 
  • In pregnancy, fetal development requires adequate vitamin B12 levels.


Marie Caudill of Cornell University on the benefits of choline for mothers and infants:

  • There is a high demand for the essential nutrient choline in pregnancy, to meet fetal needs: Choline, a methyl-donor, is necessary for epigenetic expression and for many metabolic reactions in the body; it plays multiple roles including developing myelin sheaths around nerves, increasing speed of message transmission. 
  • Higher choline intake increases DHA status in women of childbearing age. “This suggests increasing choline in pregnancy may be a way to increase DHA supply to the developing fetus.”
  • Those with higher pregnancy choline intake were less likely to have babies with neural tube defects. Increased choline intake may also ease baby’s response to stress as measured by infant cortisol level.
  • Higher maternal choline intake decreases preeclampsia risk and improves lifelong cognitive functioning in offspring (at least in baby rats). Rodent studies also show protection against Alzheimers, fetal alcohol syndrome, autism, and others.
  • Higher maternal choline intake improves infant information processing speed + other cognitive performance measures.
  • The amount of choline in cow’s milk based formula is similar to human milk (HM), but lower in soy-based formula. The form of choline in formula is different than HM. Absorption is likely best from HM. Current AI (adequate intake recommendation)  for choline is likely too low.
  • Only 8% of women achieve the recommended intake of 550 mg of choline daily. Best sources are animal source foods, which poses a challenge for those on plant-based diets. Most prenatal vitamins do not contain choline. Human milk has15x more choline than maternal blood; thus, need in lactation is great too.
  • Choline-rich foods include egg yolks, beef, chicken, fish at about 100 mg/3 oz serving. Best plant sources are legumes and cruciferous vegs, which provide 3~0 mg/serving. Overweight women and those with fatty liver disease likely need more.
    • CTM Note: Information about choline requirements and food sources may be found here.


Kimberly O’Brien of Cornell University on iron (Fe) requirements in pregnancy and lactation:

  • US recommendations on pregnancy need is based on 400 women in Finland, UK and Sweden (ethnicities not reported). Dosage of iron provided was 7X the U.S. RDA.
  • Fe-deficiency highest in African Americans


Corrine Hanson of University of Nebraska Medical Center on nutritional antioxidants during pregnancy and lactation: 

  • Levels of antioxidant nutrients (vitamins C and E, selenium, and β-carotenoids) are lowest among those living in food deserts. 
  • These nutrients fight oxidative stress, helping the body recover.
  • Take home message: we need to increase population access to fruits, vegetables, nuts and seeds.
  • Calcium(Ca)  is also a population challenge in pregnancy and lactation. However, a Cochrane review found no clear benefits of Ca supplementation.
  • Activated vitamin D has a half-life of 4 hours. Therefore, regular input of D is important. Yet studies on the impact of D supplementation have inconsistent outcomes. 
  • 20% of North American women are vitamin D deficient (<20ng/ml).
  • Response from Hanson to a later general question about nutrient supplementation: Nutrients are not benign. They are powerful bioactive chemicals. Giving replete individuals more of a specific nutrients does not usually result in good outcomes. The individual’s circumstances need to be taken into account.


Elizabeth Pearce of Boston University School of Medicine on iodine (I) needs in pregnancy and lactation:

  • Iodine levels in the population are decreasing, according to NHANES (the National Health and Nutrition Examination Survey). 
  • The most critical period for adequate iodine intake is the 1st trimester of pregnancy
  • The longest list of negative impacts of iodine deficiency accrues to the fetus, including cognitive deficiencies, increased risk of stillbirth, cretinism, etc.
  • Iodized salt has decreased I-deficiency worldwide. UK research shows lower maternal I levels in pregnancy correlate to lower child IQ, even for those with the mildest level of deficiency. 
  • Vegans and vegetarians are at greater risk for I-deficiency. 
  • Prenatal supplementation of 150 mcg/d is recommended. However, current research does not demonstrate that supplementation is effective.
  • There are potential risks of excess iodine consumption. For example, an estimated 10% of pregnant women have thyroid autoimmunity. Hypothetically, a big dose of iodine could trigger hypothyroidism in the susceptible woman and also in her child.
  • CTM: Interesting question from a participant: Could the decrease in iodine status be related to concerns about sodium intake and the use of non-iodized salt products (e.g. sea salt, artisanal salt products)?


Dr. Bailey

Regan Bailey of Purdue University on dietary supplement use during pregnancy and lactation:

  • Who takes supplements in preg/lact? 77% of pregnant women. Older women (35-44) are the most likely to do so. By ethnicity: most likely among Non-Hispanic (NH) Whites, followed by Hispanic/Mexican Americans and then NH Blacks.
  • Many prenatal vitamins (PNV) do not contain any choline. 
  • There is a lot of variability among PNVs. 
  • Many pregnant women do not consume enough of several nutrients, and almost all are at risk of excess sodium intake and insufficient iron and folate intake.


Dr. Borgelt

Laura Borgelt of University of Colorado Anschutz Medical Campus on prenatal supplement formulations:

  • Prescription vs. over-the-counter PNVs: Rx version have higher doses of Fe and folic acid. Non-Rx versions tend to contain choline and extra ingredients (e.g. botanicals).
  • Research has found that both Rx and non-Rx PNVs may have more or less of ingredients than are listed on the label. 
  • If looking for a safer PNV, look for PMVM Quality Assurance (QA) designations on the label, such as: USP, NSF, Consumer Labs. These QA seals don’t address health outcomes, but that the contents are what the label states + there are no known safety issues. 
  • Guidelines needed for safe lead levels, avoiding other potentially toxic ingredients, etc.
  • Diet is the safest source of nutrients.

CTM Note: Check out the NIH Prenatal Multivitamin + Mineral (PMVM) Calculator – your tax dollars at work! 

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