Iodine is a required nutrient for humans with limited natural dietary sources in some areas. The best foods for adding this nutrient to your diet are seafood. Iodine was the most common mineral deficiency in many areas of North America before the introduction of iodized salt.
During the 1930s, a lack of this mineral in the soil in the Midwestern states caused many people to develop goiters, an enlargement of the thyroid gland. Iodine deficiency in children can lead to mental retardation.
Following are some key functions of iodine:
Used by the thyroid gland to make thyroid hormones, which control metabolic rate and body temperature.
Supports other biochemical reactions.
Used as potassium iodide for bronchial congestion and to rebalance the body and support immune function.
Iodine occurs in seawater and thus most seafood and seaweed, including kelp. It is also found in vegetables (as long as it occurs naturally in the soil) and in milk (if farmers add it to the cow’s feed).
Iodine is a required nutrient in the amount of 150 mcg per day for adults. This supply is adequate, especially if you consume processed foods with added iodine-containing salt or add it to your food.
Toxicity is uncommon unless people consume excessive salt or kelp tablets. Deficiency can cause low thyroid function and thyroid swelling (goiter), although this is less common than it was in the past.