Iodine intake from dietary supplements among pregnant females in the US: National Health and Nutrition Examination Survey 1999–2006

Abstract

During pregnancy, there is an increased need for iodine because iodine is essential for adequate neural development and growth of the fetus. Therefore adequate iodine nutriture is critical at that time. The Estimated Average Requirement (EAR) is 160 μg. Previous reports indicate that iodine is available in only 50% of prenatal dietary supplements (DS) sold in the US. The purpose of this study was to characterize use and the amount of iodine in DS used by pregnant women in a population‐based survey, the NHANES during 1999–2006. The oversample of pregnant women 15–39 years of age during that period permitted reliable estimates on this nationally‐representative sample of 1234 pregnant women. While 78%(SE 2) of these pregnant women reported taking one or more DS in the past 30 days, only 21%(SE 2) of them reported consuming one that contained iodine. The most common amount reported on the label was 150 μg iodine/serving. Average daily iodine intake was estimated using the amount of iodine from the DS facts label, frequency of use over the past 30 days, and the amount consumed on the days the DS was taken. Mean iodine intake for iodine supplement users (e.g. pregnant women taking one or more DS containing iodine) was 125 μg (SE 6) and the median was144 μg. 76% (SE 5) of the pregnant females using a DS containing iodine met or exceeded the EAR of 160 μg. However, intakes of women using a DS not containing iodine or not using a DS should be further investigated.