Diet and Cancer
Objectives : US national surveys report that pregnant women are at risk of dietary deficiency for several key nutrients, including calcium, iron, folate, and vitamin D. Most pregnant women take prenatal multivitamins (MVM). However intake studies have used only product label information, which may lead to incorrect estimates of their impact on nutrition status. It is unknown if the label information for prescription prenatal (RxP) MVM correctly reflects the composition of these products. The objective of this study was to investigate the relationship between labeled and analytically measured content of ingredients in RxP MVM.
Methods : From a list of 338 Rx prenatal MVM sold by retail and mail order pharmacies from 06-2015 to 06-2016, a selection of representative products was generated using random sampling weighted by market share. Multiple lots of 24 products, representing 61% of the market were tested by commercial laboratories for their vitamin, mineral and docosahexaenoic acid (DHA) content. Laboratories were selected based on the results from quality control materials, including National Institute of Standards and Technology Standard Reference Materials.
The RxP MVM evaluated in this study varied in their labeled ingredient content. All RxP MVM labels listed folic acid, vitamins B-6, D, E and iron; 83-92% contained niacin, riboflavin, thiamin, and vitamins C, B-12, and zinc; and 71% contained calcium. Only 46-54% contained vitamin A, iodine and DHA. Analytical results showed mean overages of ≥ 20% for 6 vitamins (folic acid, niacin, riboflavin and vitamins A, B-12, D); 10-15% for vitamins B-6, C, E; and slightly below (-4%) label results for thiamin. For minerals and DHA, analytical content was close to labeled content, averaging 1-11% above label.
Conclusions : Many of the less expensive, highly consumed products were formulated without iodine or DHA despite recommendations for iodine supplementation from leading health authorities in the US and worldwide and data indicating that DHA may improve pregnancy outcomes. Analytical testing revealed that most RxP MVM had vitamin and mineral levels above label, with vitamin D the highest, averaging 29% above label. Thus, the intake of some nutrients from Rx prenatal MVM could be underestimated.
Funding Sources : NIH Office of Dietary Supplements and USDA Agricultural Research Service