Iodine was discovered in seaweed ash by chemist Bernard Courtois. Its name derives from the Greek word iodes, which describes the element's violet vapor. Iodine is abundant in the sea and its life forms, as well as in the soil and air of coastal areas. Since much of the world's population resides inland, iodine deficiencies are relatively common.
Iodine is Essential for Thyroid Function
Iodine is best known for its role in thyroid function. It helps the synthesis of the thyroid hormones T4 (thyroxine) and T3 (triiodothyronine). T4 and T3 play an important role in the body's control of metabolism. Iodine deficiencies may result in the enlargement of the thyroid gland, also known as goiter, which became less common in the United States after 1924, the year salt producers began fortifying their supplies with iodine. Decreased iodine levels have been linked to lower IQs in children between the ages of 6 and 16.1
Iodine Shields Your Thyroid Against Radiation
Because of iodine's affinity for thyroid tissue, exposure to low doses of radioactive iodine from nuclear fallout could lead to the development of thyroid cancer. For this reason, ingestion of potassium iodide tablets, which prevent radioactive iodine uptake by the thyroid, is recommended in the event of a nuclear accident or attack. Potassium iodide must be administered from up to 48 hours before to approximately eight hours after exposure to be effective. It is more effective in those with sufficient dietary intake.2
Iodine Alleviates Symptoms of Fibrocystic Breast Disease
Iodine may be helpful in alleviating fibrocystic breast disease, a painful condition characterized by breast cysts. In one study, women taking iodine experienced improvements in their symptoms.3 There is also evidence that links insufficient iodine intake to an increased risk of breast cancer. A study of rats treated with a breast cancer-inducing agent found a protective effect for iodine in animals that received continuous treatment.4
How to Get More Iodine
People on a low-salt diet, vegetarians, and vegans can all easily become iodine-deficient. Athletes are also at risk due to the amount of iodine lost in sweat. Iodine is found in fish, shellfish, kelp, milk, and in most salted foods (due to the addition of iodine to salt). Kelp tablets are a good source of iodine, as are many multivitamin formulas. The Institute of Medicine recommends 150 micrograms per day but larger amounts have been taken safely. The Japanese consume up to 3,000 micrograms daily with no adverse effects. Like anything, iodine has a potential for toxicity, yet its relative safety has permitted many uses in medicine. There are, however, people with a sensitivity to iodine-containing compounds who should avoid their use.
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