Too much sodium, not enough vitamins and minerals in diets of pregnant women

Regan Bailey. (Purdue University photo)
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WEST LAFAYETTE, Ind. — A new study suggests that many pregnant women are not getting the proper amounts of some vitamins and minerals, even with supplements, while many are getting potentially excessive amounts of sodium.

The new study appears in the recent editon of JAMA Network Open.

Regan Bailey, an associate professor in nutrition science in Purdue University’s College of Health and Human Sciences, led the research team.

The study looks at the dietary intake data of 1,003 pregnant women in the U.S., and researchers discovered that many of the participants consumed too little of vitamins A, C, D, E, K and B6, as well as folate, choline and minerals iron, potassium, calcium, magnesium and zinc. Almost all of the participants consumed too much sodium, and in some instances, consumed too much folic acid and iron.

“Without dietary supplements, 80 to 95% of pregnant women would fail to achieve iron recommendations,” Bailey said.

Traditionally during pregnancy, women will take additional nutritional supplements, including prenatal vitamins. In the study, almost 70% of pregnant women took a dietary supplement, primarily prenatal vitamins.

 “It appears that supplements may be necessary for most pregnant women to meet nutrient recommendations,” Bailey said. “However, our findings suggest that responsible formulations of prenatal products could help women achieve recommended intakes without the potential for excess.”

Bailey says balance, moderation and variety are ways to encourage a healthy diet for all. She also encourages pregnant women to talk to their health care provider or a registered dietitian regarding dietary questions or concerns.

Funding for this research was provided by Nestle Nutrition.

Bailey’s health research aligns with Purdue's Giant Leaps celebration, acknowledging the university’s global advancements made in health, longevity and quality of life as part of Purdue’s 150th anniversary. This is one of the four themes of the yearlong celebration’s Ideas Festival, designed to showcase Purdue as an intellectual center solving real-world issues.  

Writer: Matthew Oates, 765-496-2571, oatesw@purdue.edu; @mo_oates

Source: Regan Bailey, reganbailey@purdue.edu, @Regan_Bailey_

ABSTRACT

Usual Dietary Intakes of Pregnant Women in the United States

Regan L. Bailey, PhD, MPH, RD; Susan G. Pac, MS, RD; Victor L. Fulgoni III, PhD; Kathleen C. Reidy, DrPH, RD; Patrick M. Catalano, MD 

Importance: Nutrition during pregnancy is a critical dimension not only for women’s health but also for the lifelong health of the offspring. Very limited national data exist on the usual dietary intakes of pregnant women.

Objective: To estimate total usual nutrient intakes (from foods and dietary supplements) and the population prevalence of meeting or exceeding the National Academies of Sciences, Engineering, and Medicine Dietary Reference Intake recommendations among pregnant US women.

Design, Setting, and Participants: A cross-sectional analysis was performed of a nationally representative sample of 1003 pregnant US women aged 20 to 40 years from the 2001-2014 National Health and Nutrition Examination Survey.

Exposure: Usual dietary intakes assessed by two 24-hour dietary recalls (including dietary supplements) adjusted for within-person variation using the National Cancer Institute method.

Main Outcomes and Measures: The proportion of women at risk of inadequate dietary intake as determined by the Estimated Average Requirement, the proportion of women assumed to have adequate dietary intake as determined by the Adequate Intake, and the proportion of women at risk of excess dietary intake as determined by the Tolerable Upper Intake Level. Demographic differences between pregnant and nonpregnant women were compared with t tests.

Results: As representative of the US population, this sample of 1003 pregnant women had a mean (SE) age of 28.0 (0.3) years, was predominantly non-Hispanic white (mean [SE], 54.5% [3.1%]), and was at above 185% of the income to poverty ratio (mean [SE], 56.8% [3.0%]). Most pregnant women used a dietary supplement (mean [SE], 69.8% [2.3%]). A total of 10% or more of pregnant women had a total usual intake that is less than the Estimated Average Requirement for magnesium (mean [SE], 47.5% [2.8%]), vitamin D (mean [SE], 46.4% [2.7%]), vitamin E (mean [SE], 43.3% [2.7%]), iron (mean [SE], 36.2% [2.8%]), vitamin A (mean [SE], 15.5% [2.1%]), folate (mean [SE], 16.4% [1.6%]), calcium (mean [SE], 12.9% [2.4%]), vitamin C (mean [SE], 11.5% [1.9%]), vitamin B6 (mean [SE], 11.5% [1.5%]), and zinc (mean [SE], 10.9% [1.9%]). Some pregnant women exceeded the Adequate Intake for potassium (mean [SE], 41.7% [2.9%]), choline (mean [SE], 7.9% [3.2%]), and vitamin K (mean [SE], 47.9% [4.3%]). Most women exceeded the Tolerable Upper Intake Level for sodium (mean [SE], 95.0% [2.2%]), and some women exceeded the Tolerable Upper Intake Level of folic acid (mean [SE], 33.4% [2.8%]), iron (mean [SE], 27.9% [2.8%]), calcium (mean [SE], 3.0% [0.8%]), and zinc (mean [SE], 7.1% [1.6%]). For iron, the prevalence of an at-risk intake from foods alone was lower among women who used supplements (mean [SE], 80.3% [4.3%]) than those who did not use supplements (mean [SE], 95.3% [7.3%]); however, supplement use increased the risk of excessive iron and folic acid intakes given the amounts that are being consumed from supplemental products.

Conclusions and Relevance: This study suggests that a significant number of pregnant women are not meeting recommendations for vitamins D, C, A, B6, K, and E, as well as folate, choline, iron, calcium, potassium, magnesium, and zinc even with the use of dietary supplements. Almost all pregnant women in this study were at risk of excessive consumption of sodium, and many were at risk of excessive consumption of folic acid and iron. Improved dietary guidance to help pregnant women meet but not exceed dietary recommendations is warranted.