Author: Dr. Bonnie Brock, NMD, RD, MPH
In addition to being critical for thyroid health, iodine is also found in the cerebrospinal fluid, in the ciliary body of the eye, in the lining of the GI tract and salivary glands. Iodine is important for hormone production, acts as an anti-microbial agent and is important for normal growth and development of children. Iodine also seems to play a role in breast health, as iodine deficiency contributes to fibrocystic breasts and lead to breast cancer if left unchecked.
The first medical use of iodine was to treat the enlargement of the thyroid in the throat, medically referred to as a goiter. When iodine levels are low, the thyroid gland enlarges to try to capture more iodine so it can produce enough thyroid hormone. A doctor in the early 1800s noticed silver miners, who drank the runoff water from the mines, did not develop goiters. It was determined this water contained high levels of iodine. People began eating the iodine-laden salt from in and around the mines to prevent goiters and eventually most table salt in the United States was “iodized’.
The thyroid gland produces the hormone thyroxine, or T4, which is made of four molecules of iodine bound together and is predominantly inactive. Certain cells in the liver, muscles, gut and kidney use specific enzymes to transform T4 into triiodothyronine (T3) through a process called de-iodination, or the cleaving off of one molecule of iodine. T3 is considered “active” because cells that have receptors to receive thyroid hormone are better able to use T3 than T4. Thyroid hormone regulates the rate at which your body uses calories (metabolism), the heartrate, body temperature, the speed at which food moves through the GI tract and bone loss and replacement. Due to its role in thyroid health and hormone function in general, adequate iodine intake is critical for good health.
While the idea of chemically adding iodine to salt to protect people from deficiency was good in theory, it has not proven to be ideal in practice. Firstly, iodized salt is typically highly refined, bleached and devoid of other minerals and nutrients. Refined salt can contribute to other diseases and health conditions if used as the main source of salt. Much better to use unrefined, natural salt, that is rich in a balance of minerals and nutrients. Secondly, it has been determined that humans only absorb about 10% of the iodine in refined salt. Iodine found naturally in seaweed, ocean fish and other foods has a much higher bioavailability. (see our other blog post this month for a great recipe using seaweed). Iodine deficiency has risen with the commercial use of bromine in the baking industry. Bromine competes for absorption and utilization with iodine, so as the consumption of bromine increased with baked goods in the diet, the levels of iodine in the body became more deficient.
Beyond eating iodine-rich foods, one can supplement to be sire needs are met. I recommend patients use Lugol’s Iodine solution, which is an iodine/potassium iodide solution in water that can be taken by mouth when mixed with water or juice, or placed on skin to be absorbed transdermally.
