Most Dietary supplements not meeting nutrient needs of women during pregnancy

"Convenient and affordable products that fill the gap between food-based intake and estimated pregnancy requirements without inducing excess intake are required to support pregnant women and their offspring," the researchers wrote in their study. They found affordable dietary supplements that provide critical nutrients in proper doses for pregnant women are virtually nonexistent.

Previous studies have suggested that inadequate or excessive nutrient intake during pregnancy may lead to adverse maternal and offspring health outcomes. Dietary supplements are common (more than 70% of pregnant women). Still, it does not prevent the risk of improper intake of all nutrients and causes more than 25% of pregnant women to consume more than the maximum intake levels of iron and folic acid, which may lead to adverse health effects. This indicates that formulations of commonly used dietary supplements are not adequately addressing the gap between food-based intake and estimated pregnancy requirements.

To fill this knowledge gap, Katherine A. Sauder, University of Colorado Anschutz Medical Campus, Aurora, CO, USA, and colleagues aimed to estimate the supplementation doses required to help most pregnant women achieve the recommended consumption without exceeding upper limits for critical prenatal nutrients and to identify US dietary supplements providing these doses.

The analysis considered six nutrients with the strongest evidence for a potential benefit for health outcomes of mother and child: vitamin D, vitamin A, folate/folic acid, iron, calcium, and omega-3 fatty acids (ω-3 FAs). The authors aim to provide target doses for supplementation of these critical nutrients and produce a list of products currently available in the US that give these target doses.

24-h dietary recalls were conducted in 2450 pregnant participants aged 14–50 from 2007 to 2019. The authors calculated the target supplementation doses required to shift 90% of participants to consume above the estimated average need and keep 90% below the tolerable upper limit.

The authors reported the following findings:

• The target dose for supplementation was ≥198 mcg retinol activity equivalents of total vitamin A (with ≤2063 mcg preformed retinol); 169–720 mcg dietary folate equivalents of folic acid; 7–91 mcg vitamin D; 13–22 mg iron; 383–943 mg calcium; and ≥59 mg ω-3 fatty acids.
• Out of 20,547 dietary supplements (comprising 421 prenatal products), 69 products (33 prenatal) contained all six nutrients; 7 products (2 prenatal) contained target doses for five nutrients.
• Only one product (not a prenatal) contained target doses for all six nutrients, but it currently costs ∼USD200/mo and requires seven tablets per daily serving.

Based on the findings, the researchers need clarification of the lower and upper dosing thresholds associated with specific health outcomes.

"Products' reformulation or development that maximize the number of pregnant women receiving adequate (but not too much) vitamin D, vitamin A, calcium, folic acid, iron, and ω-3 FAs is required," they wrote.

They conclude, "Despite patients believing they are getting everything they need with their product purchase, they fall short of guideline-recommended requirements."

Reference:

Sauder, K. A., Couzens, G. L., Bailey, R. L., Hockett, C. W., Switkowski, K. M., Lyall, K., Kerver, J. M., Dabelea, D., Maldonado, L. E., O'Connor, T. G., Deoni, S. C., Glueck, D. H., & Catellier, D. J. (2023). Selecting a dietary supplement with appropriate dosing for 6 key nutrients in pregnancy. The American Journal of Clinical Nutrition, 117(4), 823-829. https://doi.org/10.1016/j.ajcnut.2022.12.018