Use of Iodine-Containing Dietary Supplements Remains Low among Women of Reproductive Age in the United States: NHANES 2011–2014

Abstract

In the United States, the American Thyroid Association recommends that women take a dietary supplement containing 150 µg of iodine 3 months prior to conception and while pregnant and lactating to support fetal growth and neurological development. We used data from the National Health and Nutrition Examination Survey 2011–2014 to describe the use of dietary supplements with and without iodine in the past 30 days among 2155 non-pregnant, non-lactating (NPNL) women; 122 pregnant women; and 61 lactating women. Among NPNL women, 45.3% (95% Confidence Interval [CI]: 42.0, 48.6) used any dietary supplement and 14.8% (95% CI: 12.7, 16.8) used a dietary supplement with iodine in the past 30 days. Non-Hispanic black and Hispanic women were less likely to use any dietary supplement as well as one with iodine, than non-Hispanic white or non-Hispanic Asian women (p < 0.05). Among pregnant women, 72.2% (95% CI: 65.8, 78.6) used any dietary supplement; however, only 17.8% (95% CI: 11.4, 24.3) used a dietary supplement with iodine. Among lactating women, 75.0% (95% CI: 63.0, 87.0) used a dietary supplement; however, only 19.0% (95% CI: 8.8, 29.2) used a dietary supplement with iodine. Among NPNL women using a supplement with iodine, median daily iodine intake was 75.0 µg. Self-reported data suggests that the use of iodine containing dietary supplements among pregnant and lactating women remains low in contrast with current recommendations.

Estimation of Total Usual Dietary Intakes of Pregnant Women in the United States

“…12 Concerns exist of excessive intakes of some nutrients during pregnancy, especially folic acid and vitamin A, 13,14 while low intake of iron and iodine in reproductive-aged US women has also been of concern. 15 Thus, ensuring that pregnant and reproductive-aged women have adequate, but not excessive, dietary intakes is crucial to understand how to best tailor public health messaging and policy during this critical life stage. The purpose of this study was to report the usual nutrient intakes from food and dietary supplements for pregnant women using data from the National Health and Nutrition Examination Survey (NHANES).…”

Women’s health: optimal nutrition throughout the lifecycle

“…A few other studies using national data focused only on supplements containing folic acid, iron, or iodine during pregnancy and before pregnancy [ 28 , 40 , 65 , 76 ]. For example, pregnant women who use supplements containing these nutrients, the average amounts exceed or approach the UL, just from the DS alone: folic acid at 817 mcg (UL = 1000 µg) and iron at 48 mg (UL = 45 mg) per day.…”

“…Similarly, the American Thyroid Association recommends that all women who are pregnant use a dietary supplement with a minimum of 150 µg of iodine a day [ 6 , 138 ]. While most prenatal supplements contain the recommended amount of iodine [ 65 , 145 ], their use is low among pregnant women (20.4% consuming 116 µg/day from supplements on average) [ 65 , 76 , 132 ]. Urinary iodine concentrations suggest that many reproductive aged and pregnant women have risk iodine inadequacy [ 65 , 76 ].…”

Current iodine nutrition status in Poland (2017): is the Polish model of obligatory iodine prophylaxis able to eliminate iodine deficiency in the population?

“…In some countries generally considered long-term iodine-sufficient, such as the USA, the iodine status of pregnant women had worsened in recent years (median UIC in NHANES 2001-2006: 153 μg/l; NHANES 2006-2010: 129 μg/l) (74)(75)(76) . The suboptimal iodine nutrition during gestation may also result from poor adherence to iodine-containing supplements (62,77,78) .…”