Iodine is vital for good thyroid function, which in turn is essential for good health. Iodine deficiency was prevalent in the U.S. before the iodization of salt became a common practice in the 1920s [Journal of the American Dietetics Association 79 (1981): p.17].
Causes and Development
Some otherwise healthful foods contain goitrogens – substances which can interfere with iodine
uptake or hormone release from the thyroid gland
. These foods are generally only a concern if iodine intake is low. Consumption of brassicas, such as cabbage, Brussels sprouts, broccoli and cauliflower, increase the requirements for iodine, especially if consumed raw. Soybeans, raw flaxseed, cassava (used in tapioca), sweet potatoes, lima beans, maize and millet also increase the requirements for iodine.
Some individuals deliberately take kelp to try to lose weight by over stimulating the thyroid
. This is a dangerous practice.
Diagnosis and Tests
intake of less than 20mcg per day is considered severe deficiency; 20-50mcg per day is considered moderate deficiency and 50-100mcg per day is considered mild deficiency.
Treatment and Prevention
In the US, iodised salt is widely used and some other foods are fortified with iodine
. In Canada all table salt is iodised. The UK has no iodine fortification strategy for plant foods or salt.
deficiency during pregnancy and early infancy can result in cretinism (irreversible mental retardation and severe motor impairments).