There has been much speculation around the link of low iodine levels in the body with breast disease. Research is showing that it is likely due to a two part mechanism. Iodine is used in the thyroid gland to make thyroid hormone, is important for growth and development, and is important during fetal growth to develop the nervous system. When there is deficiency of iodine in the diet, the thyroid gland will swell into what is called a goiter. Historically, iodine deficiency was endemic in mountainous regions of the United States and Mexico, and in the so called “goiter belt” around the Great Lakes. It was because of goiter epidemics that iodine was introduced to table salt.
How is the thyroid related to the breast?
It has been seen that low thyroid function correlates with breast disease development. This link is likely due to the changes in metabolic effects from the low thyroid function and a frank lack of iodine as both thyroid and breast tissue use iodine. It has been shown that low iodine causes changes in tissue growth in both types of tissue. With autoimmune thyroid diseases, iodine use is blocked in the thyroid and potentially in the breast as well, causing tissue nutrient deficiencies. In Japan where seaweed and other rich dietary sources of iodine are consumed, there is a very low incidence of breast disease.
How does iodine protect the breast tissue?
It has been postulated that iodine may act as an antioxidant in the breast. Iodine is known to metabolize estrogens that cause estrogen related hormone growth. It can also suppress tumor growth and increase tumor cell death. In my practice, I have seen the benefits of using iodine with breast cancer and fibrocystic breasts (painful lumpy breasts).
How is iodine tested?
The most accurate way to test iodine is through a 24 hour urine specimen. Testing iodine levels is useful because it gives a baseline for treatment.
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