[Assessment on dietary iodine intake in three areas of Zhejiang province, 2009].

Objective: To assess the level of dietary iodine intake in three areas of Zhejiang and the related policy on universal salt iodization in the province.

Methods: The study involved 497 residents from 180 families living in Hangzhou, Taizhou, Zhoushan cities, representing coastal and inland areas in Zhejiang province in 2009. A total diet study was applied to obtain the typical diet samples at three study areas through food consumption, aggregation, sampling and preparation processes. The contents of iodine in diet samples were determined by tetramethylammonium hydroxide extraction-inductively coupled plasma-mass spectrometry. The amount of dietary iodine intake was calculated by timing the food consumption data and the iodine content in different dietary samples. The safety of dietary iodine intake was evaluated according to the recommended nutrient intake (RNI) and tolerable upper intake level (UL) published by the Chinese Nutrition Society in 2001.

Results: The dietary iodine intake of reference person in three areas of Zhejiang province was 421.0 µg/d. The levels of P5, P25, median, P75, P90, P95 dietary iodine intake were 145.7 µg/d, 267.6 µg/d, 358.5 µg/d, 495.6 µg/d, 774.1 µg/d and 1273.0 µg/d respectively. Daily dietary iodine intake at UL accounted for 5.2%, 87.5% and 7.2% of all the participants respectively. Without considering the loss through cooking, salt iodine provided 81.6% of the dietary iodine source. The resources of dietary iodine would include vegetables, cereals and marine food, proportionally, as 57.2%, 13.0% and 8.5%, respectively. Participants whose daily dietary iodine intake exceeded the UL level would consume more marine algae products than those whose dietary iodine intakes were lower than RNI or between RNI-UL.

Conclusion: Dietary iodine intake among most residents and their average level were among reasonable ranges. Meanwhile, deficiency and excess of iodine intake coexisted. Salt iodine was the main resource of dietary iodine. Participants whose dietary iodine intakes exceeding the UL level, would prefer consume more marine algae products.