Objective: To assess the potential risk of dietary iodine insufficiency of population in non-high-iodine areas (water iodine < 150 microg/L) in China.
Method: The dietary iodine intake of 13 age-sex population groups were estimated by combining the data of iodine intake from food, table salt and drinking water. Two conditions were considered: consuming iodized salt or non-iodized salt. The data of food and table salt consumption were derived from the Chinese National Nutrition and Health Survey in 2002. Water consumption was calculated as the recommended water intake. Iodine contents of food, table salt and water were calculated from China Food Composition Table and iodine surveillance data.
Results: Under the condition of consuming iodized salt, the average iodine intake of all population groups was higher than the Recommended Nutrient Intake (RNI), while the iodine intakes of individuals above Upper Limits (UL) and below RNI were 5.8% and 13.4% respectively, and the iodine intake of individuals lower than the Estimated Average Requirement (EAR) was 9.4% in adults above 18 years of age (including pregnant and lactating women). If non-iodized salt was consumed, the average iodine intake of most sex-age population groups was higher than RNI, but the iodine intake of 97.6% of individuals would be lower than RNI, while the iodine intake of 97.4% of adults would be lower than EAR. The contribution of iodine from table salt was much higher than that from drinking water and food in the condition of consuming iodized salt, while food was the predominant contributor of dietary iodine in the condition of consuming non-iodized salt.
Conclusion: The health risk of iodine deficiency was higher than that of iodine excess in areas where water iodine was < 150 p.g/L in China, and the risk of iodine insufficiency was much higher if non-iodized salt was consumed. Iodized salt should be the main sources of dietary iodine intake for population in areas where water iodine was < 150 microg/L in China.