Iodized salt refers to the table salt that contains potassium iodate. Due to iodine deficiency in many regions of China, iodized salt is mandatory for consumption. However, there are several misconceptions about iodized salt in our daily lives. Let's summarize the misconceptions about iodized salt below.
Misconception 1: Salt does not have an expiration date
Most people believe that household salt does not expire and remains salty no matter how long it is stored. This is because the main chemical component of salt is sodium chloride, which is responsible for its salty taste. Sodium chloride is highly stable in its chemical properties, so the taste cannot change regardless of how long it is stored. However, being salty does not mean it cannot go bad. In addition to sodium chloride, salt also contains potassium iodide. Although the properties of potassium iodide are relatively stable, the iodine content in salt can decrease over time due to evaporation caused by light exposure, wind, and heat, affecting its iodine supplementation effect. Therefore, salt does have an expiration date, and it is recommended to store it for no longer than three years.
Misconception 2: Iodized salt causes a high incidence of thyroid cancer
The high incidence of thyroid diseases cannot solely be attributed to iodized salt. Other factors such as genetic factors, environmental factors, and emotional factors also play a significant role. The World Health Organization (WHO) believes that a daily iodine intake of less than 1000 micrograms is generally safe, while the Chinese Nutrition Society recommends 800 micrograms. Based on China's iodine addition limit of 30 milligrams per kilogram, consuming 600 micrograms of iodine would require consuming 20 grams of salt. The average salt intake for Chinese people is around 12 grams, and the recommended intake of salt is only 5-6 grams. Therefore, it is unlikely that excessive iodine intake caused by consuming iodized salt will occur.
Misconception 3: There is already an excess of iodine, so there is no need to consume iodized salt
"Risk Assessment of Iodine Nutrition in Chinese Salt Iodization and Residents" shows that the overall iodine intake of residents in areas with low water iodine content is generally suitable and safe. However, if iodized salt is not used, approximately 97.6% of people would be at risk of iodine deficiency. Since most regions in China are low in water iodine content, the contribution of iodized salt to preventing iodine deficiency is much greater than the risk of excessive iodine intake. Considering the impact of water iodine on iodine intake, the country has adopted a more flexible approach in iodine fortification policies, such as discontinuing the supply of iodized salt in high water iodine areas in 2006.
Misconception 4: Coastal areas have abundant seafood, so there is no need to consume iodized salt
Data shows that seaweed and other traditional iodine-rich foods contribute very little to iodine intake (less than 4%). Urinary iodine levels and dietary iodine intake indicate that iodine intake is suitable and safe for coastal residents after consuming iodized salt. Iodized salt does not cause excessive iodine intake for them.
