The ruling was a strategy to ensure that an iodine deficiency didn't develop in the American diet. And it worked. Today, iodine deficiency has been virtually eliminated domestically. Unfortunately, about 1.6 billion people, mainly in underdeveloped countries are still plagued by a variety of disorders caused by a lack of this mineral in their diets.
The primary function of iodine is to keep the thyroid gland healthy and capable of manufacturing thyroxine, a vital hormone needed throughout the body. This hormone helps to regulate metabolism (how quickly and efficiently calories are burned), to control the physical and mental growth of children (insufficient iodine in a pregnant woman can cause cretinism in a fetus), and to break down fats and proteins.
In these and many other ways, iodine is, at least indirectly, responsible for maintaining some of the most fundamental biological functions of the body.
Insufficient iodine (which results in too little thyroxine) can lead to such symptoms as fatigue, dry skin, an increase in blood fats, a hoarse throat, delayed reflexes, and reduced mental clarity.
As much as 75% of the body's iodine is stored in the butterfly-shaped thyroid gland in the front of the throat; the rest is distributed throughout the body. If a person is iodine-deficient, a goiter (a large growth at the base of the neck) may develop as the thyroid works overtime trying to make enough thyroxine hormone for the body to function normally. Interestingly, in rare cases, taking an excessive amount of iodine will enlarge the gland and cause a goiter as well.
Recently, international-aid researchers reported the pooled results of 10 studies carried out in countries where iron-deficiency disorders are common. They found multiple consequences of inadequate iodine in children, including impaired motor skills, diminished muscle strength and coordination, poor manual dexterity, and other problems.
Dietary sources of iodine are plentiful. For most Americans, a deficiency in iodine is not a risk. One teaspoon of iodized salt contains more than 300 mcg of iodine, so it is not difficult to obtain or exceed the small amount needed to meet the daily requirement. The RDA for iodine is 150 mcg a day for adults.
Other sources of iodine include dairy products made from milk produced by cows grazing in coastal soil, as well as fruits and vegetables grown in coastal soil. Various vegetables from the sea, such as kelp and seaweed, contain very high amounts of iodine as well. Commercially prepared baked goods, such as cakes and breads, frequently contain dough conditioners that have iodine. Most salty, high-sodium processed snack foods, however, contain very little iodized salt and almost no iodine.
The trace mineral is also found in most multivitamin and mineral supplements. Concentrated sea kelp tablets are another potent source of iodine.
