Written by Carol Petersen, RPh, CNP – Women’s International Pharmacy
The world abounds with substances that affect hormone balance. It is widely accepted that that there are many organic substances that affect hormone activity in the body. For example, soy has estrogen-like qualities and ginseng acts as an adrenal adaptogen. We can use these organic substances in ways that are beneficial to the body. On the other hand, organic substances like phthalates, PCBs and BPA mimic estrogens in a negative way. They create a burden of too much estrogen activity in the body.
Researchers are now turning to inorganic sources of hormone disruption. In 2006, Dr. Philippa Darbre published a paper that identified many metals that have an effect on estrogen receptors. These effects include: altering gene expression, estrogenic activity, and displacing estrogens from estrogen receptors. Metals that have been identified to exert an influence on estrogen receptors include aluminum, antimony, arsenite, barium, cadmium, chromium, cobalt, copper, lead, mercury, nickel, selenite, tin, and vanadate. These metals are referred to as metalloestrogens. The paper also identified metalloestrogen activity at progesterone, testosterone and glucocorticoid (hydrocortisone-like) receptors. For example, cadmium has been shown to produce testosterone activity, displace testosterone from testosterone receptors and affect gene changes. Dr. Darbre concludes that all steroid hormone receptors may be affected.
Some metalloestrogens are essential minerals. Cobalt, chromium, copper, and nickel are all needed in trace amounts for normal human body function. When the amounts of these minerals exceed the amount needed by the body, they begin to interfere with the hormone receptors.
Other metalloestrogens, such as cadmium, aluminum, and lead, are not needed by the body in any amount. Cadmium is problematic because the human body doesn’t have an enzyme system to eliminate it once we are exposed. Making matters worse, the kidneys reabsorb cadmium rather than eliminate it. The amount of cadmium in our bodies continues to increase as we age. Common sources of cadmium, outside of industrial uses, include cigarette smoke and certain foods due to cadmium pollution in our environment. Cadmium may be a trigger for endometriosis. Several studies point to an association between the presence of cadmium in the body and endometrial tissue proliferation. One especially interesting study found melatonin was able to block the estrogenic effect of cadmium in endometrial tissue.
Lead acts as a metalloestrogen by occupying hormone receptors. Unsurprisingly, lead contributes to a number of health conditions. The Environmental Protection Agency (EPA) recognizes lead can cause a number of problems for women. After menopause, increased levels of lead in the body increase one’s risk for hypertension, atherosclerosis, reduced kidney function, and decreased cognitive functioning with symptoms similar to dementia. Osteoporosis, another condition common in menopause, can cause lead to be released into the body as bone breaks down. Those of us who have been exposed to lead paints and leaded gasoline have higher levels of lead in our bones, causing higher levels of lead in our bodies as lead is released from our bones. (For more information, read our article Lead Toxicity and Disease.)
As research expands and we dig deeper into hormone balance issues, more information emerges to help us solve the riddle of hormone imbalance. The effects of metalloestrogens are not always considered by busy practitioners. Furthermore, many are not trained to help reduce the body’s load of metalloestrogens. Three medical groups that focus on reducing metalloestrogens in the body are the International College of Integrated Medicine, the American College for Advancement in Medicine, and the American Association of Naturopathic Physicians.
- Darbre PD. Metalloestrogens: An Emerging Class of Inorganic Xenoestrogens With Potential to Add to the Oestrogenic Burden of the Human Breast. J Appl Toxicol. 2006 May-Jun;26(3):191-7. DOI:10.1002/jat.1135.
- U.S. Environmental Protection Agency Aging and Sustainability List Serve
- Silva N, et al. Metalloestrogen cadmium stimulates proliferation of stromal cells derived from the eutopic endometrium of women with endometriosis.Taiwan J Obstet Gynecol. 2013 Dec;52(4):540-5.
- Jackson LW, Zullo MD, Goldberg JM. The association between heavy metals, endometriosis and uterine myomas among premenopausal women: National Health and Nutrition Examination Survey 1999 – 2002. Hum Reprod. 2008 Mar;23(3):679-87. DOI: 10.1093/humrep/dem394. Epub 2008 Jan 12.
- Chemical of the Day. Metalloestrogens. https://chemicaloftheday.squarespace.com/most-controversial/2014/9/4/metalloestrogens.html. September 2014. Last accessed September 2019.
- Martínez-Campa C, et al. Melatonin inhibits both ER alpha activation and breast cancer cell proliferation induced by a metalloestrogen, cadmium. J Pineal Res. 2006 May;40(4):291-6.