Misconception 1: Iodized salt is the primary cause of thyroid disease. A Swiss study found that the incidence of thyroid tumors gradually decreased after salt iodization. The World Health Organization (WHO) also notes that thyroid cancer rates are lower in areas with adequate iodine intake compared to iodine-deficient regions. Therefore, the claim that "iodized salt causes high thyroid cancer rates" currently lacks scientific basis.The high incidence of thyroid diseases cannot overlook factors beyond iodized salt, such as genetic predisposition, environmental influences, and emotional stress. The WHO deems daily iodine intake below 1,000 micrograms generally safe, while the Chinese Nutrition Society recommends 800 micrograms.Based on China's maximum iodization limit of 30 mg/kg, consuming 600 μg of iodine would require eating 20 grams of salt. The average Chinese person consumes about 12 grams of salt daily, while the recommended intake is only 5–6 grams. Therefore, it is highly unlikely that iodized salt could lead to iodine overdose.The Risk Assessment of Iodized Salt and Iodine Nutrition Status in China indicates that iodine intake among residents in low-water-iodine areas (where drinking water has low iodine content) is generally adequate and safe. However, without iodized salt, approximately 97.6% of the population would be at risk of iodine deficiency.Since most regions in China are classified as low-iodine water areas, iodized salt contributes far more to preventing iodine deficiency than it poses a risk of iodine excess. Considering the impact of water iodine on overall intake, the national policy on iodine fortification has adopted a more flexible approach. For instance, China ceased supplying iodized salt in high-iodine water areas in 2006.
Misconception 3: Coastal regions have abundant seafood, so iodized salt is unnecessary.Data indicates that traditional iodine-rich foods like kelp and laver contribute minimally to iodine intake (less than 4%). Urinary iodine levels and dietary iodine intake show that coastal residents maintain adequate and safe iodine levels when consuming iodized salt, with no evidence of iodine overconsumption.Conversely, coastal residents' iodine nutritional status lags behind inland rural areas within the same province. For instance, in coastal regions of Zhejiang, Shanghai, and Liaoning, the proportion of pregnant women with iodine deficiency reaches as high as 46%. Therefore, coastal residents should also consume iodized salt in appropriate amounts.
That concludes our overview of the three major misconceptions about iodized salt. We hope this has provided you with valuable insights. Finally, we sincerely wish you good health and happiness.