Group 1 - The core issue of iodine deficiency remains a public health concern in China, with a significant portion of the population still lacking adequate iodine intake despite improvements over the years [2][4][3] - The recommended daily iodine intake for pregnant women is 230 micrograms, which is double that of adults, highlighting the importance of sufficient iodine during pregnancy to prevent developmental issues in infants [1][2] - The implementation of universal salt iodization has been effective in reducing the prevalence of iodine deficiency disorders, with a reported iodized salt coverage rate of 94.8% and a suitable iodine nutrition status among pregnant women [3][4] Group 2 - Despite the progress made, there is a growing misconception among the public that iodine deficiency is no longer a concern, leading to increased consumption of non-iodized salt [4][6] - Iodine is essential for the synthesis of thyroid hormones, which are crucial for metabolism and overall health; a lack of iodine can lead to various health issues, including thyroid dysfunction [4][6] - Epidemiological studies indicate that iodine deficiency is a risk factor for thyroid nodules, and adequate iodine intake may help reduce the incidence of such conditions [7][6] Group 3 - The majority of salt consumed in China is from well and rock salt (87%), with iodized salt being the recommended option to meet iodine needs while also addressing sodium intake [8] - In coastal regions, despite the availability of iodine-rich foods like seaweed, the consumption frequency is low, making iodized salt a necessary source of iodine for residents [9][8] - The public health strategy of iodizing salt is recognized as a safe, effective, and low-cost method to ensure adequate iodine intake across the population [7][3]

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]