Dairy food consumption is beneficially linked with iodine status in US children and adults: National Health and Nutrition Examination Surveys 2001-2018.

Objectives: The objective of this study was to determine the association between the consumption of dairy foods with urinary iodine concentration (UIC) and iodine deficiency risk in a nationally representative sample of the US population.

Design, Setting And Participants: 24-hour dietary recall data and laboratory data for UIC (μg/l) from subjects 2+ years old US population participating in National Health and Nutrition Examination Surveys 2001-2018 were used ( 26 838) for analyses after adjusting for demographic covariates. Significant associations were assessed at < 0·05.

Results: Mean intakes of total dairy were 2·21, 2·17 and 1·70 cup equivalents (cup eq) among those 2-8, 9-18 and 19+ years, respectively. Of the dairy components, intake of milk was highest followed by cheese and yogurt for all age groups. Total dairy intakes were positively associated with UIC among those 2-8 years ( = 29·9 ± 9·9 μg/l urine/cup eq dairy) and 9-18 years ( = 26·0 ± 4·8 μg/l urine/cup eq dairy) but not associated among those 19+ years. Total dairy intakes were associated with lowered risks (30 %, 21 % and 20 % for among 2-8, 9-18 and 19+ years, respectively) of being classified as iodine insufficient (UIC < 100 μg/l) or lowered risk (47 %, 30 % and 26 % among 2-8, 9-18 and 19+ years, respectively) of being classified as iodine severely deficient (UIC < 20 μg/l).

Conclusions: The results indicate that dairy foods are beneficially associated with UIC and lowered iodine deficiency risk.