Iodine's primary purpose is the manufacture of thyroxine. Thyroxine is the thyroid hormone which controls much of the work of the thyroid, a small gland located at the front and base of your neck. Iodine and thyroxine are critically important in the prevention of hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid).

Iodine also has a multitude of secondary, but very important, functions in your body. These include supercharging the white blood cells' microbe-killing capabilities; ensuring healthy overall body development, particularly skin and hair; maintaining acute mental function; control of bodily energy generation; and preventing surplus mucous buildup in the body (especially important to those suffering from lung diseases).

Iodine deficiency can be serious, affecting your immune system and thyroid function. If you have a high score here, don't buy iodine supplements. Some people are very sensitive to iodine, and you could have a serious allergic reaction. Also, excess iodine intake may affect thyroid function and cause other problems such as acne.

Sea vegetables (arame, bladder wrack, dulse, hijiki, kelp, kombu, nori, sea palm and wakame) are a good food source of iodine and are also good sources of proteins, carbohydrates, antioxidants, vitamins and other minerals. They can be chopped in the food processor or blender and sprinkled over food, or added to soup after it is cooked. Kelp tablets and powdered kelp can be a good supplementary source of iodine, if the kelp comes from an area of low water pollution. Kelp from polluted waters may be contaminated with toxic metals. Seafood is another good source of iodine, but may also be contaminated by polluted water.