Iodine has many functions, including promoting growth and development, participating in brain development, regulating metabolism, maintaining the physiological function of the pituitary gland, and playing an important role in other organs and systems. The thyroid gland is the organ with the strongest ability to accumulate iodine. After blood iodine is taken up by the thyroid gland, thyroid hormones are generated in the epithelial cells of thyroid follicles. Thyroid hormones can stimulate the development and maturation of ossification centers, leading to cartilage ossification and promoting the growth of long bones and teeth. During the critical period of brain development, the development of the nervous system depends on thyroid hormones. During this period, insufficient or insufficient intake of iodine can cause varying degrees of brain development delay, and in severe cases, it may develop into "dementia". Even if iodine or thyroid hormones are supplemented in the future, it cannot be reversed. 

Thyroid hormones can also promote the synthesis and breakdown metabolism of proteins, fats, and sugars. By increasing oxygen consumption and generating energy, they can affect the basal metabolic rate, enhance material and energy metabolism, maintain metabolism, and maintain body temperature. So, if there is insufficient iodine, it may cause slow mental response, weight gain, and lack of vitality. Therefore, iodine is of great significance in maintaining our body's health.