Why you need it?
Iodine is a chemical element. The body needs iodine but cannot make it. The needed iodine must come from the diet. As a rule, there is very little iodine in food, unless it has been added during processing, which is now the case with salt. Most of the world’s iodine is found in the ocean, where it is concentrated by sea life, especially seaweed.

The thyroid gland needs iodine to make hormones. If the thyroid doesn’t have enough iodine to do its job, feedback systems in the body cause the thyroid to work harder. This can cause an enlarged thyroid gland (goiter), which becomes evident as a swollen neck.
Deficiency Symptoms:
Iodine deficiency and the resulting low levels of thyroid hormone can cause women to stop ovulating, leading to infertility. Iodine deficiency can also lead to an autoimmune disease of the thyroid and may increase the risk of getting thyroid cancer. Some researchers think that iodine deficiency might also increase the risk of other cancers such as prostate, breast, endometrial, and ovarian cancer.

Iodine deficiency during pregnancy is serious for both the mother and the baby. It can lead to high blood pressure during pregnancy for the mother, and mental retardation for the baby. Iodine plays an important role in development of the central nervous system. In extreme cases, iodine deficiency can lead to cretinism, a disorder that involves severely stunted physical and mental growth.

Iodine deficiency is a common world health problem. The most recognized form of deficiency is goiter. Additionally, across the globe iodine deficiency is thought to be the most common preventable cause of mental retardation. Early in the twentieth century, iodine deficiency was common in the US and Canada, but the addition of iodine to salt has improved public health.