The issue of iodine is often a dilemma for people. Whether to eat more iodine or less iodine is always a toss-up. The thyroid gland is the processing plant for thyroid hormones, and iodine is the raw material for making thyroid hormones. Therefore, a lack of iodine can lead to a shortage of raw materials, compensatory enlargement of the thyroid gland, goiter, thyroid nodules, hypothyroidism, etc. Whether excessive iodine can cause thyroid disease is not yet conclusive from an evidence-based medical perspective. It is only due to the current high prevalence of thyroid disorders and the widespread consumption of iodized salt that some people have made this assumption. But in any case, moderate levels of iodine intake should be what we are looking for. But it would be a mistake to eat non-iodized salt for the whole family just because of thyroid nodules. Most areas in China are iodine deficient, including coastal areas. In fact, we mainly get iodine from the soil, but for natural reasons a lot of iodine from the soil is lost to the sea by rain, so seawater is rich in iodine. Among them, nori and kelp have the highest iodine content, but most people only eat them occasionally, and they often have to soak them in water and rinse them several times, so a lot of inorganic iodine is lost from the water. The iodine content of sea fish and sea shrimp also decreases after cooking. The contribution of seafood to dietary iodine is also very low (1.6%-3.0%), so consume iodized salt. If you usually consume more seafood, you can reduce your intake of iodized salt appropriately by consuming low iodized salt, or by cooking with less salt. If you are pregnant or have children at home, it is important to ensure iodine intake because they need about 40% more iodine than normal adults. So for people who have thyroid nodules or if you feel that your seafood intake is high, consider consuming low iodized salt instead of non-iodized salt. For those who have hyperthyroidism you can consume non-iodized salt during treatment.