Iodine has a close relationship with thyroid disease. In clinical practice, we often encounter patients who have the question, “Doctor, since I have thyroid disease, that is, big neck disease, shouldn’t I take more iodine and eat more kelp to be right?” In fact, in modern cities, especially in the eastern coastal cities, thyroid disease caused by iodine deficiency is rare, so most patients with thyroid disease do not need to eat a lot of kelp, nori, etc. to increase iodine intake. The thyroid gland is an important endocrine organ in the neck of the body, which secretes mainly thyroid hormones, in addition to calcitonin. Iodine is an important raw material for the synthesis of thyroid hormones, and iodine deficiency can cause certain thyroid disorders, while excessive iodine intake is also the cause of some thyroid disorders. Since the thyroid gland itself can be affected by a variety of diseases, and diseases of other body systems can sometimes affect the function of the thyroid gland, it is not correct to say in general terms that patients with thyroid disease should or should not take iodine supplements. Some thyroid disorders require large amounts of iodine supplementation, while others require only the iodine in a normal diet, and some thyroid disorders require a strict restriction of iodine intake in order to facilitate remission of the disease. Category I: Thyroid diseases requiring iodine supplementation: These diseases can be collectively referred to as iodine deficiency diseases, and their treatment means that they require specialized iodine supplementation in order to prevent and treat the disease. Some parts of China, especially the central and western mountainous areas, are iodine deficient because they are far from the sea and have low iodine content in the air and water. In the past, before salt iodization was introduced in China, iodine was generally lacking in the diets of the residents there, so a disease called “endemic goiter”, commonly known as “big neck disease”, occurred most frequently. If a woman suffers from this disease during pregnancy, it will cause neurological and physical developmental disorders in the baby, resulting in dwarfism and mental retardation, also commonly known as “cretinism”, also known as “cretinism”. In China, iodine deficiency disorders have been basically eliminated after salt iodization nationwide. Especially for those who live in urban areas, it is important not to take iodine supplements as soon as you notice swelling in your neck, but to go to the hospital promptly. This is because it is likely that you do not have a thyroid disease that requires iodine supplementation, and if you take a large amount of iodine supplementation, it may also affect the results of some recent tests, thus delaying the diagnosis and treatment of the disease. Category 2: Thyroid diseases that do not require iodine supplementation: These are the most common of the thyroid diseases that do not require large amounts of iodine supplementation and are usually treated with a normal diet. Examples are thyroid swellings (nodules), various types of thyroiditis, primary hypothyroidism, etc. The thyroid gland can cause morphological or functional abnormalities if such diseases occur, which can lead to corresponding symptoms and signs. For example, swelling of the neck with pain or lumps, which are local manifestations, or swelling, coldness, weakness, bradycardia, and other systemic manifestations. This type of disease is usually treated by medication or surgery, and iodine supplementation or iodine prohibition does not have a significant impact on the treatment effect. Therefore, patients can still eat normally and do not have to worry about how the iodine content in their diet will affect the treatment effect. The third category: thyroid diseases that require iodine prohibition: There is a category of thyroid diseases called “hyperthyroidism”, or “hyperthyroidism” for short, the most common of which is hyperthyroidism caused by Graves’ disease, in addition to hyperthyroidism caused by high iodine intake ( In addition, there is also hyperthyroidism (or other iodine excess disease) caused by high iodine intake, and we must be careful not to eat foods rich in iodine for this disease. It is important not to confuse hyperthyroidism with the commonly known “big neck disease”, as they are not the same disease at all. “In addition to an enlarged thyroid gland, hyperthyroidism is also associated with protruding eyes, shaky hands, excessive sweating, panic attacks and increased bowel movements. In most cases of hyperthyroidism, iodine supplementation is not allowed and iodine abstinence is required so that the treatment of the disease will not be affected. The iodine prohibition we are talking about here mainly refers to not eating foods or drugs rich in iodine, such as sea plants like kelp and seaweed, western drugs like amiodarone and iodine tablets, or traditional Chinese medicines like seaweed, kombu and oyster, which should be avoided as much as possible; secondly, it refers to sea animals such as sea fish, sea shrimp and sea crab, which have medium iodine content. This kind of things should be eaten as little as possible, but sometimes a small amount of them will not have too much effect on the disease. In addition, there are some foods or herbal medicines that contain small amounts of iodine, which are generally not to be avoided. For iodized salt, hyperthyroidism patients do not need to have too many contraindications either. The iodine in iodized salt is easy to sublimate and volatilize, so it should be kept in a cool place away from light. If we take it to a ventilated place to dry, it will accelerate the sublimation of iodine.