Most Supplements Do Not Offer Suitable Prenatal Nutrition, Study Suggests

A new study has explored the landscape of supplements used by pregnant women in the United States (US). The data reveals that 99% of supplements do not provide suitable amounts of some of the key micronutrients missing from women’s diets.

The research is published in The American Journal of Clinical Nutrition.

Striking a balance in nutrients

Around 75% of pregnant women in the US take prenatal vitamin supplements, as insufficient consumption of micronutrients such as folic acid or iron can have negative health outcomes for both mother and baby. On the other hand, consuming excessive amounts of certain nutrients, such as vitamin A, can have negative effects. Therefore, it is important to strike a balance in nutrient consumption, which requires choosing the right prenatal vitamin. The researchers in the current study aimed to investigate US dietary supplements on the market, estimating the doses required to meet the recommended intake of key nutrients while not exceeding their upper limits.

“Nutrition is critical for a healthy mom and a healthy baby,” said Dr. Katherine Sauder, lead author of the study and associate professor of pediatrics at the University of Colorado School of Medicine. “Too little of certain nutrients can cause pre-term birth, low birthweight, birth defects and other health challenges. At the same time, too much could change how a baby’s body develops and their risk of having health problems in the future. That’s why eating a balanced diet and choosing a good prenatal vitamin is so important.”

Finding a suitable supplement

Sauder and colleagues followed 2,450 pregnant study participants who each provided at least one 24-hour recall, in which they listed all food and drink consumed in the previous 24-hour period.

The researchers estimated the levels of vitamin A, vitamin D, folic acid, calcium, iron and omega-3 fatty acids that each participant consumed through food alone and used this data to calculate how much they needed in order to meet the nutritional guidelines set out by the National Institutes of Health. They then analyzed this information and compared it against over 20,000 supplements currently available in the US.

The authors note that of all the 20,000 prenatal and general vitamin supplements they assessed, they found only one that had the potential to supply optimal amounts of all 6 nutrients to pregnant patients. However, this supplement – which was not a prenatal product – comes at significant cost of ~$200 per month and requires taking 7 pills for each daily serving.

“This research will inform pregnant patients and their doctors about key nutrients they may be missing in their diet and help them choose prenatal vitamins that can provide the nutrients they need,” added Sauder. “Dietary supplement manufacturers can also use these results to inform better dosing in their products.”

Filling the nutritional gap

“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,” the researchers write.

Sauder noted that the study emphasizes the need for more affordable and convenient prenatal supplements that also provide the right amounts of important nutrients, and she hopes that this information can be used to help improve nutritional care during pregnancy. Additionally, she stressed that additional research on nutrients available in food is necessary to help pregnant patients meet nutritional guidelines through their diet.

Reference: Sauder KA, Couzens GL, Bailey RL, et al. Selecting a dietary supplement with appropriate dosing for 6 key nutrients in pregnancy. Am J Clin Nutr. 2023;117(4):823-829. doi: 10.1016/j.ajcnut.2022.12.018

This article is a rework of a press release issued by the University of Colorado Anschutz Medical Campus. Material has been edited for length and content.