Endocrine Disruptors II: Bisphenol A Lurking in our Kitchen

March 18, 2009

By Kathryn Au

Bisphenol A is a man-made organic compound found in many household products in the form of epoxy resin and polycarbonate plastic. Epoxy resin is used to line the insides of canned foods to protect the food from metal contamination, and polycarbonate plastic is used to make baby bottles, water bottles, eyeglass lenses, CDs and other household electronics, white dental fillings and dental sealants, sports helmets, and children’s toys. Bisphenol A (BPA) often leaches out of the plastic in food containers and canned goods into food and drinks. Scientists are alarmed about its chemical properties as an endocrine disruptor when it enters the body through food and drinks.

Endocrine disruptors are substances that affect the endocrine system. The endocrine system—whose network of organs includes the thyroid gland, adrenal gland, pancreas, ovaries, and testes, among others—regulates the release of hormones. Endocrine-disrupting substances act like hormones, putting the endocrine system out of balance. BPA, for example, mimics a type of estrogen hormone called estradiol, which drives the development of sexual traits. Sufficient exposure to such endocrine disruptors can lead to damage to sexual organs, decreased sperm count, and early onset of puberty.

Many studies in the last decade have attempted to investigate the effects of BPA as an endocrine disruptor. Experiments have found links between BPA and growth of cancer cells in breast cancer, ovarian cancer, and prostate cancer in lab mice. Exposure to BPA may also be related to reproductive problems, neurological problems, and metabolic problems, such as obesity and diabetes.

America’s growing diabetes and obesity epidemic is usually blamed on lifestyle factors like poor diet and a lack of exercise, but research suggests that environmental factors like exposure to BPA may also play a role. BPA has been shown to suppress the release of a hormone that allows the body to recognize insulin [1, 2]. The body’s inability to recognize and process insulin results in Type II diabetes. A survey linking BPA to diabetes and heart disease found that obese people and young adults have higher amounts of BPA in their body [3]. This could mean that more and more young people are at risk for obesity—and thus for diabetes and heart disease.

Low-income minorities and people who live in rural areas with poor access to fresh foods—both characteristics of many Native American populations—are more likely to eat cheaper canned goods that leach BPA than the average American. This puts many at a high risk for health conditions that scientists suggest are related to BPA. Indeed, Native Americans currently suffer from absurdly high rates of diabetes and obesity.

On the other hand, supporters of BPA claim that no evidence exists on BPA’s direct effect on humans, since most studies have focused on lab animals. They argue that numerous government agencies and scientific bodies have declared the chemical safe at current exposure levels (see www.bisphenol-a.org). However, opponents of BPA counter that these supporters are using misinformation to keep BPA on store shelves. They also point out that current safety levels of BPA were established from studies conducted in the 1980s using outdated methods. Many new studies have found negative effects of BPA on lab animals at low doses similar to what humans might get.

That said, people concerned about BPA have several options to reduce or avoid exposure to BPA. Although it is a substance found everywhere in household items, it only enters the body through food and drink. Therefore, the key to controlling exposure lies in the choice of food products and food containers. Here are a few suggestions:

• Use stainless steel or glass containers instead of polycarbonate water bottles. When using a polycarbonate water bottle, do not pour a hot drink into it.
• Reduce consumption of canned foods and beverages, especially ravioli and chicken noodle soup. Tomatoes and other acidic foods may also leach more BPA from cans.
• Use ceramic or glass plates to microwave and store foods instead of plastic.
• Beware of food containers made from recycled paper like pizza boxes and coffee cups. Bring your own mug to coffeeshops if possible.

Recently, BPA has been attracting a great deal of international attention. Last April Canada placed a ban on baby products containing BPA, and many stores and brands are voluntarily offering BPA-free alternatives. Although the U.S. Food and Drug Administration (FDA) has been insisting on the safety of current levels of BPA in food products, the scientific community is pressuring it to reconsider the evidence. In the meantime, consumers should be informed about the science on BPA so that they can make their own choice when buying food products.

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Suggested Links
http://www.bisphenolafree.org
http://www.ourstolenfuture.org
http://www.thegreenguide.com
http://www.healthychild.org
http://www.cspinet.org/nah/bpa.html

References
[1] Hugo, E. R., Brandebourg, T. D., Woo, J. G., Loftus, J., Alexander, J.W., Ben-Jonathan, N. (2008). Bisphenol A at environmentally relevant doses inhibits adiponectin release from human adipose tissue explants and adipocytes. Environmental Health Perspectives 116(12): 1642-1647.
[2] Alonso-Magdalena, P., Morimoto, S., Ripoll, C., Fuentes, E., Nadal, A. (2006). The estrogenic effect of bisphenol A disrupts pancreatic β-cell function in vivo and induces insulin resistance. Environmental Health Perspectives 114(1): 106-112. doi:10.1289/ehp.8451.
[3] Lang, I. A., Galloway, T. S., Scarlett, A., Henley, W.E., Depledge, M., Wallace, R.B., Melzer, D. (2008). Association of urinary bisphenol A concentration with medical disorders and laboratory abnormalities in adults. The Journal of the American Medical Association. 300(11): 1303-1310. doi:10.1001/jama.300.11.1303