For the past 60 years doctors have been taught that iodine was important for the thyroid but nowhere else in the body and only in microgram amounts i.e. just enough to prevent goiter, an enlargement of the thyroid gland due to iodine deficiency. However, over the past 40 years, research by Bernard Eskin M.D. OB-GYN department at Drexel University and many others indicates that after the thyroid, the breasts and ovaries concentrate the most iodine of all other organs. The rest of the body’s iodine is stored in the fat, muscle and skin. Adequate iodine is necessary for the development of normal breast architecture. Milk from lactating breasts contains four times more of the ingested iodine than the amount taken up by the thyroid gland. Research dating back to the 1970’s indicates a definite relationship between fibrocystic breast disease (affecting two thirds of American women) and iodine deficiency. Fibrocystic breast disease is usually considered a benign condition however recent research shows that the cystic changes in breast structure may be a precursor to breast cancer. Iodine has been shown to be extremely effective in treating fibrocystic breast disease. It is actually the most researched essential nutrient in treating this condition.
The Estrogen-Iodine Breast Cancer Connection
Not only are the ovaries the primary source of estrogens in the body, they also have the second highest concentration of iodine. Iodine deficiency produces changes in the ovarian production of estrogen as well as changes in the estrogen receptors in the breasts. If there is a whole body deficiency of iodine, the ovaries will produce more estrogen and estrogen receptors in the breast increase their sensitivity to estrogen. These changes will increase the risk of developing pathological changes in the breast which can lead to breast cancer. Drs Stoddard, Eskin and colleagues reported in 2008: “We suggest that the protective effects of iodine/iodide on breast disease may be in part through the inhibition or modulation of estrogen pathways. Data presented suggests that iodine/iodide may inhibit the estrogen response through 1) up-regulating proteins involved in estrogen metabolism (specifically through increasing the liver detoxification of estrogens), and 2) decreasing BRCA1 inhibition thus permitting its inhibition of estrogen responsive transcription. These data open the way for further defining pathways impacted by the essential element, iodine, in the cellular physiology of extrathyroidal tissues, particularly the breast.” They are now working to see if iodine/iodide can be used with Tamoxifen or as a substitute for it.
How Much Iodine for Breast Health?
The milligram amounts of iodine researched for fibrocystic breast disease over the past 30 years is over a thousand of times greater than the RDA of 150 micrograms (mcg) established in 1980. The Japanese daily diet of seaweed contains 12-13 milligrams of iodine. In coastal areas the daily iodine intake may be closer to 50 mg. These amounts are enough to give the average PCP or endocrinologist a fit of apoplexy since they are trained to believe that any amounts higher than the U.S RDA standard are “dangerous”. The Japanese have one of the lowest rates of breast cancer in the world. To determine iodine deficiency, the World Health Organization uses a 24 hour urine test as they monitor iodine intake around the world. Research in 2012 in the journal Experimental and Clinical Endocrinology & Diabetes states: “Routine annual urinary iodine determination is recommended and should target type 2 diabetes patients at risk of thyroid dysfunction.” Unfortunately urine iodine testing is not performed by the major laboratories s and doctors are not trained to order it. However there are several specialty labs in the US who do perform the test. This should be done before starting on an iodine program and be supervised by a knowlegable physician.
Recipe for Breast Health Disaster
The National Health and Nutrition Examination Survey (NHANES) between 1971-74 and 2000 showed that iodine levels have dropped 50% in the U.S. During this same time the amount of iodine related minerals (called halides) such as bromine (Mountain Dew, commercial baked goods, sports drinks, flame retardant in car upholstery and bedding, hot tubs, pesticides) chlorine derivatives such as perchlorate (contaminate in Colorado river water irrigating crops) and fluoride (fluorinated water, tooth paste) all of which block the beneficial iodine effects in all tissues of the body have increased exponentially. The NHANES survey of 1988-1994 indicated that 15% of U.S. women were iodine deficient based on urine levels, i.e. about one in seven women which roughly corresponds to current rates of breast cancer. Medical reports over the past 100 years indicate a relationship between hypothyroidism and breast cancer. Other studies show a two fold increase in breast cancer in women who take thyroid hormone replacement. It is time for a re-evaluation of this misunderstood essential nutrient.
Hunter Yost M.D. practices Functional and Nutritional Medicine in Tucson.