The human endocrine system is complicated and finely balanced. Too much of one hormone, not enough of another, and the results can be a lot worse than moodiness or bad skin. Cancers and other disorders have been linked to hormone imbalances, or “endocrine disruption.” Our bodies are sensitive to even small amounts of endocrine disrupting chemicals, which is why they are often measured in parts per trillion.
Endocrine disruptors, which can either mimic or block naturally occurring hormones, can be found in places you might not normally associate with hormones. Here are some examples of how you might be exposed in daily life.
Food containers: You can eat organic meat, dairy and produce until the cows come home, but if you use plastic containers containing BPA to hold your leftovers, lunches, or filtered water, you’re not doing yourself any favors. BPA, or bisphenol-A, is a known endocrine disruptor. It mimics estrogen in the body, and has been linked with cancer (especially breast cancer), reproductive problems, obesity, early puberty, heart disease, and liver failure.
Plastic water bottles are the primary source of BPA exposure for most people. Food cans are another common source, since many cans are lined with BPA. Plastic items with recycling label #7 often contain BPA. According to an NIH study (2009), BPA is found in the bodies of 93% of Americans – and it lingers in the body for days after exposure.
Soy: Some plants contain naturally occurring hormone analogs (chemicals that mimic hormones in chemical makeup and function). For example, soy contains genistein and daidzein, which are estrogen analogs. Phytoestrogens can actually have health benefits, depending on who you are. Some of these (which are similar to the benefits of estrogen) include reduced lowered risk of osteoporosis, heart disease, breast cancer, and menopausal symptoms. However, if you are a breast cancer patient, or a male, soy products may not be for you.
Herbicides: Atrazine is commonly used on corn crops, and people are exposed to it through consuming corn products and even drinking water, due to runoff from fields. This endocrine disruptor has been linked to breast cancer, delayed puberty, and prostate problems. To demonstrate how strongly atrazine disrupts hormones, note that even at low levels, it causes feminization of male frogs (male frogs go through a sex-change, becoming egg-laying females).
Pesticides: Organophosphate pesticides, one of the most commonly used classes of pesticides, have been linked in many studies to deficits in brain development, behavior and fertility. These endocrine disruptors interfere with the way testosterone communicates with cells, and exposure can reduce testosterone levels and cause thyroid problems.
In a 2011 study of 37 pesticides and fungicides commonly used on food crops, 30 were found to blocked or mimicked male hormones. Sixteen of the 30 had no previously known hormonal activity, indicating that the health effects of pesticides have yet to be thoroughly understood.
Of the tested compounds, those that blocked male hormones (androgens) most effectively included the insecticide fenitrothion, an organophosphate used on orchard fruits, grains, rice, vegetables and other crops. Other endocrine disruptors identified included the fungicides fludioxonil, fenhexamid, dimethomorph and imazalil. Fungicides, used on crops such as strawberries, are commonly found as residue in food, in part because they are applied close to harvest.
Scented Products: Most commercially produced products that have a scent (such as room fresheners, scented candles, even hand lotions and soaps) contain chemicals called phthalates. In addition to products containing the ingredient “fragrance,” phthalates are also found in plastic food containers and plastic wrap with the recycling label #3.
Pthalates trigger apoptosis, or cell death, in testicular cells. As endocrine disruptors, they also reduce sperm count and motility, are linked to birth defects in the male reproductive system, and are associated with obesity, diabetes, and thyroid problems.
Non-Stick Cookware: If you use non-stick pans for cooking, you are exposing yourself to PFCs, or perfluorinated chemicals. One of these compounds, PFOA, never biodegrades; once it has been produced, it stays in the environment forever. PFOA, an endocrine disruptor, has been linked with poor sperm quality, low birth weight, kidney disease, thyroid disease, and high cholesterol. It is believed to act by altering steroid hormone production and affecting ovarian function.
How Endocrine Disruptors Work: Endocrine disruptors can function in any of several ways.
- They can mimic naturally occurring hormones (causing the body to behave as if it has too much of a particular hormone).
- They can block naturally occurring hormones from binding to receptors, by “docking” there themselves (causing the body to behave as if it has a deficit of a particular hormone).
- Or they can interfere with or block the way hormones are produced, controlled, or broken down in the body (causing a response completely different than would occur with undisrupted hormones).
Given the serious effects of endocrine disruptors, it may be worth your while to eliminate as many as possible. For example, avoid plastic bottles and food containers, and stick with organic produce (avoiding herbicides and pesticides).
For further reading:
Biello, D. (2009). Like a Guest That Won’t Leave, BPA Lingers in the Human Body. Scientific American. Published online January 28, 2009 at http://www.scientificamerican.com/article/bpa-lingers-in-human-body/.
Cone, M. (2011). New tests reveal many pesticides block male hormones. Environmental Health News. Published online at http://www.environmentalhealthnews.org/ehs/news/pesticides-block-male-hormones.
Environmental Working Group. (2013). Dirty Dozen Endocrine Disruptors: 12 Hormone-Altering Chemicals and How to Avoid Them. Published online October 28, 2013 at http://www.ewg.org/research/dirty-dozen-list-endocrine-disruptors.
National Institute of Health Sciences. (2015). Endocrine Disruptors. Published online at http://www.niehs.nih.gov/health/topics/agents/endocrine/.
Orton, F., et al. (2011). Widely Used Pesticides with Previously Unknown Endocrine Activity Revealed as in Vitro Antiandrogens. Environ Health Perspect. 2011 June; 119(6): 794–800. doi: 10.1289/ehp.1002895.
Patisaul, H., and W. Jefferson. (2010). The pros and cons of phytoestrogens. Frontiers in Neuroendocrinology, 31(4), pp. 400-419. http://www.sciencedirect.com/science/article/pii/S0091302210000257
White, S., S. Fenton, and E. Hines. (2011). Endocrine disrupting properties of perfluorooctanoic acid. J Steroid Biochem Mol Biol. 2011 Oct;127(1-2):16-26. doi: 10.1016/j.jsbmb.2011.03.011.