May 15th is the 31st "Day for the Prevention and Control of Iodine Deficiency Disorders" in China. This year, the National Health Commission has set the theme of "Salt Iodization to Prevent Diseases, Balance Nutrition and Health". Iodine deficiency disease is a syndrome caused by insufficient iodine intake in the external environment, resulting in insufficient synthesis of thyroid hormones as the main pathogenesis. It includes endemic goiter, endemic cretinism, endemic subclinical cretinism, and infertility, miscarriage, premature birth, stillbirth, and congenital malformations that affect fertility. These conditions were previously named endemic goiter and endemic cretinism, now collectively referred to as iodine deficiency disease, to more comprehensively reflect various health problems caused by iodine deficiency. The clinical manifestations of iodine deficiency disease vary depending on the degree and duration of iodine deficiency, as well as the patient's physical condition. For adults, iodine deficiency may lead to symptoms such as chills, poor mental health, constipation, and decreased memory. They may also doze off during the day due to a lack of thyroid hormone, which slows down the body's basal metabolic rate. For minors, iodine deficiency may affect the development and growth of the central nervous system, manifested as poor academic performance, delayed response, and short stature. In clinical practice, this condition is called dementia. For pregnant women, iodine deficiency may lead to incomplete development of the embryonic central nervous system, strange facial features, and lower weight at birth. The main causes of iodine deficiency disease are due to environmental iodine deficiency and improper diet. Some areas far from coastal areas and mountainous areas with relatively high altitudes have very low iodine content in soil and water, especially in areas that have been eroded by glaciers and flooded plains. In addition, if the dietary structure is unreasonable and you do not eat foods rich in iodine, such as seafood, seaweed, seaweed, seaweed, etc., it is also easy to lead to iodine deficiency in the body. The harm of iodine deficiency disease presents a very broad spectrum of diseases, so it is defined as a "syndrome", including: the most common endemic goiter (large neck disease), the most severe endemic cretinism (dullness), and various adverse pregnancy outcomes caused by iodine deficiency. Current research suggests that mild iodine deficiency during pregnancy can lead to mild developmental damage. This kind of damage is difficult to detect because it cannot be compared, and once it occurs, it cannot be recovered through nutritional enhancement/treatment/training, etc. Therefore, pregnant women and fetuses are of utmost importance in preventing and controlling iodine deficiency disease. According to the "Reference Intake of Dietary Nutrients for Chinese Residents (WS/T 578-2017)" standard, it is recommended that ordinary adults should consume no less than 120 micrograms of iodine per day and no more than 600 micrograms of iodine per day; Pregnant women should consume no less than 230 micrograms of iodine per day, while nursing mothers should consume no less than 240 micrograms of iodine per day. In order to prevent and treat iodine deficiency disease, the following measures can be taken: dietary adjustment: increase the intake of iodine rich foods such as seaweed and seaweed, especially pregnant women, lactating women, and children in the growth and development stage, and special attention should be paid to whether the intake of iodine is sufficient. Iodization of table salt: Adding iodine to table salt is an effective preventive measure for iodine deficiency. Iodized salt is the main means of implementing the national salt iodization plan, and residents can purchase and use iodized salt in their daily lives. Stay healthy