Hypothyroidism, as the name implies, is the opposite of hyperthyroidism, where all body systems are in a hyperactive state. In clinical practice, patients often have the question, “The doctor has diagnosed me with hyperthyroidism, should I avoid iodine diet or iodine-rich diet?” The problem of not being able to distinguish between hyperthyroidism and hypothyroidism is a common one. Here are some of the things about hypothyroidism. 1. What is hypothyroidism? Hypothyroidism is a disease caused by a decrease in the synthesis and secretion of thyroid hormones or a decrease in their physiological effect on the body’s metabolism. According to its cause, it is divided into three categories: primary hypothyroidism, secondary hypothyroidism and peripheral hypothyroidism. The causes are different and so are the principles of treatment. 2, hypothyroidism precautions 1) compared with hyperthyroidism, hypothyroidism treatment is relatively simple, only a certain amount of daily supplementation of thyroid hormone (such as eugenol or Raitis) can be. Except for a few hypothyroidism (such as subacute thyroiditis and drug-induced hypothyroidism) which can be completely cured, most hypothyroidism (mainly Hashimoto’s thyroiditis-induced hypothyroidism) is a permanent disease and requires lifelong treatment. (2) Initial treatment requires 4-6 weeks of rechecking of thyroid function, and 2-4 weeks of rechecking of abnormal thyroid function during pregnancy. After the condition is stabilized, thyroid function should be rechecked regularly, and the replacement dose of thyroid hormone should be adjusted in a timely manner according to the test results. If the replacement dose is too large, it will cause hyperthyroidism such as tachycardia, excessive sweating and excitement; if the replacement dose is insufficient, the patient will not be able to correct hypometabolic symptoms such as coldness, low sweating, poor appetite, weakness and low body temperature; Hint: Because of the cold climate in winter, the body’s demand for heat increases, so hypothyroid patients need to increase the replacement dose of thyroid hormone in winter; 3) Hypothyroid patients need to clarify the cause first The cause of hypothyroidism should be identified first, and a high iodine diet should not be rushed. Iodine is an important raw material for the synthesis of thyroid hormones. Many patients take it for granted that they should have a high iodine diet if they have hypothyroidism, but in fact, the need for additional iodine supplementation depends on the cause of hypothyroidism. If hypothyroidism is caused by simple iodine deficiency (e.g. endemic goiter), then iodine supplementation can be appropriate under the guidance of a doctor; if hypothyroidism is caused by Hashimoto’s thyroiditis, then a low iodine diet with restrictions on kelp, nori and various seafood is required. If hypothyroidism is caused by Hashimoto’s thyroiditis, a low iodine diet is required, and kelp, nori and various seafood should be restricted, because a high iodine diet will increase the concentration of thyroid peroxidase antibodies (TPOAb) and induce and aggravate autoimmune thyroiditis. At the same time, it is necessary to eat less fatty and high cholesterol foods, so as not to exacerbate the disorder of lipid metabolism; try to avoid the consumption of goiter-promoting fruits and vegetables, such as cabbage, radish, potatoes, soybeans, peas, peanuts and walnuts.