Iodine Recommended Daily Allowance

Iodine Recommended Daily Allowance
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Why Iodine is Important

Iodine is an essential nutrient for good health. One of the most important functions of iodine in the body is related to the thyroid gland, which is located at the front of the throat. Iodine is necessary for the production of the thyroid hormones T3 (triiodothyronine) and T4 (thyroxine), which play a critical role in many physiological processes including regulation of metabolism, growth, development and reproduction. Thyroid hormone T3 binds to receptors in the brain and liver to regulate gene expression in these organs.

Iodine has a positive effect on the symptoms of fibrocystic breast condition, a disorder causing painful lumps in the breasts. Results of clinical trials have shown that a significant percentage of women who were given aqueous molecular iodine experienced improvement of symptoms, indicating that iodine may be therapeutically useful for treating this condition.

Symptoms of Iodine Deficiency

Iodine deficiency can cause a variety of serious health problems. One of the most visible symptoms of iodine deficiency is goiter, an enlargement of the thyroid gland that appears as a swelling on the neck. Since iodine is required for the production of thyroid hormone, if the body is not getting enough iodine, it tries to compensate by overproducing thyroid stimulating hormone (TSH), causing the thyroid gland to become enlarged. Iodine deficiency can also cause hypothyroidism, with symptoms of depression, fatigue, weakness and weight gain.

Iodine deficiency of the mother during pregnancy can cause severe problems in prenatal development, including increased frequency of birth defects, miscarriage, and stillbirths, as well as a condition known as cretinism in the newborn infant. Symptoms of cretinism include physical and mental retardation and deafness. Insufficient amounts of iodine in infants can increase the risk of infant mortality, as well as impair normal brain development.

The recommended daily allowance of iodine for adults is 150 micrograms (mcg) per day. In industrialized countries, iodine is added to table salt. If iodized salt is used regularly for cooking and seasoning, it will supply a sufficient amount of iodine in the diet. Ocean water contains iodine, and one of the best food sources of iodine is seaweed such as kelp or wakame. Fish and seafood such as cod, shrimp and tuna also contain iodine, but the amount varies depending on where the fish was caught. Other food sources of iodine include eggs, dairy products such as milk, cheese and yogurt, navy beans, baked potatoes with the peels on, and turkey. Vegetables may contain iodine, but it depends on the iodine content of the soil in which they are grown.

Vegetarians or vegans who do not eat seafood or dairy, and individuals who are on a low sodium diet and cannot add iodized salt to their food can get the iodine recommended daily allowance from seaweed, but if this is unavailable or undesirable, they may consider taking a vitamin and mineral supplement containing iodine.


Image Credit:

NIH, US Federal Government, Wikimedia Commons