Diet quality and its relationship with iodine status in pregnant women living in a Brazilian region where table salt is iodine-fortified according to public health policies.

Abstract

Objective: Conditions related to iodine status (IS) during pregnancy should be addressed to improve public health strategies. The aim of this study was to analyze the relationship between diet quality (DQ), assessed by the adapted Healthy Eating Index-2015 (HEI-2015), and IS in pregnant women from a Brazilian coastal state where public health policies assure iodine-fortified table salt in concentrations ranging from 15 to 45 mg/kg.

Subjects and methods: In a cross-sectional study, 199 participants were evaluated on three different days during their first trimester of pregnancy. At every visit, a urinary spot sample was requested to assess the urinary iodine concentration (UIC), and a 24-hour dietary recall related to the time at which the urine was collected was also performed. Total and component scores were estimated for the HEI-2015. The association between DQ and the IS was evaluated, considering an adequate UIC (150-249 μg/L) as the reference group (RG).

Results: The median total score for the HEI-2015 was 45.8 points, which was slightly better (48.1 points) in the insufficient UIC (UIC <150-249 μg/L) than in the RG (41.3 points). In the "more than adequate" and "excessive" IS groups, the scores were 40.7 and 44.6 points, respectively.

Conclusion: Pregnant women with insufficient IS had better DQ and higher consumption of fruits and vegetables, as did those with lower intake of refined grains. We suppose that these groups benefit from iodine supplementation during pregnancy even when they live in a coastal state where table salt is fortified with iodine. In contrast, excessive UIC was related to worse intake of "whole fruits", "total fruits" and "total vegetables". The results suggest that diet quality is related to iodine status in the studied population. Pregnant women with better diet quality, especially those with high consumption of total protein foods, fruits and vegetables and low consumption of refined grains, may be at risk for iodine insufficiency. The necessity of iodine supplementation for pregnant women should be better explored even in regions where iodine-fortified table salt is adopted as a public health policy.