2. Maintain the physiological function of pituitary gland;
3. Promote development: The height, weight, growth and development of bones and muscles and sexual development of developing children depend on thyroxine. If iodine is deficient at this stage, it will lead to the child's developmental delay;
4. Promote brain development: In the initial stage of brain development (from pregnancy to 2 years after birth), the development of human nervous system must rely on thyroxine. If there is a lack of iodine in the diet during this period, the baby's brain development will fall behind, which is seriously called "dementia" in clinic, and this process is irreversible. Even after iodine supplementation, it is impossible to return to normal.