Core Viewpoint - The article emphasizes the importance of iodine as an essential micronutrient for human metabolism and growth, highlighting the need for continuous scientific iodine supplementation to promote health development, especially in the context of iodine deficiency diseases in China [1] Group 1: Iodine Deficiency and Its Effects - Iodine deficiency diseases are a group of conditions caused by inadequate iodine nutrition, leading to reduced thyroid hormone levels, particularly affecting brain development in children, resulting in lower IQ [1] - In adults, the most noticeable symptom of iodine deficiency is goiter, which can cause visible swelling in the neck and may lead to respiratory and swallowing difficulties in severe cases [1] Group 2: Sources and Recommendations for Iodine Intake - The primary sources of iodine for residents in China are iodized salt, food, and drinking water, with an average daily intake of about 10 micrograms from water and 25 to 50 micrograms from food [1] - The most convenient and effective method for iodine supplementation is the consumption of iodized salt [1] Group 3: Alternative Iodine Supplementation Methods - Other methods for iodine supplementation include oral iodine oil capsules, iodine-containing medications, and iodine-rich foods such as kelp and nori, especially for women of childbearing age, pregnant women, and breastfeeding women under professional guidance [2] - While iodized salt is important, it is also crucial to control overall salt intake, with the 2022 Chinese Dietary Guidelines recommending a maximum of 5 grams of salt per day for adults [2] Group 4: Populations Not Suitable for Iodized Salt - Two groups of people should avoid iodized salt: those with autoimmune thyroid diseases (such as hyperthyroidism and thyroiditis) who may need to follow medical advice regarding iodine intake, and residents in high-iodine water areas who already receive sufficient iodine from their diet and water [2]