Iodine deficiency can cause hypothyroidism, anemia, loss of appetite, weakness, etc. Women are more likely to be affected by iodine deficiency than men, and children in their growing years are also more likely to be affected by iodine deficiency. In the early stage of iodine deficiency, there may be no clinical symptoms, only mild diffuse enlargement of the thyroid gland without pain. In a few cases of marked enlargement, there may be symptoms such as difficulty in breathing, difficulty in swallowing, hoarseness and coughing. If iodine deficiency is prolonged, it can affect the neurological development of the brain in children, manifesting itself in varying degrees of mental deficiencies, low learning ability, and can also cause thick neck disease. If severe iodine deficiency, it can also cause endemic cretinism, which is manifested as children being dull, stupid, deaf and mute, leading to children’s non-development or growth retardation. In the case of pregnant women, it can lead to fetal death, congenital malformations, miscarriage, or premature birth. In the case of non-pregnant women, severe iodine deficiency can cause menstrual disorders or even amenorrhea. In the case of adults, it can lead to decreased physical strength and labor force, easy fatigue, decreased physical fitness, loss of appetite, anemia, and so on. Normally, you should eat a little more food that is high in iodine, such as kelp, seafood fish, lobster, nori, etc., to avoid these irreversible damages caused by iodine deficiency.