It’s invisible, tasteless and odorless and yet it is found in many of the foods and beverages that we consume. It is BPA, short for bisphenol A.
BPA is a synthetic estrogen that has measurable biological effects. What is it doing in our food?
The December issue of Consumer Reports (CR) revealed that many common products, including some brands of canned green beans, vegetable soup and chicken noodle soup, contain levels of BPA that are surprising. Experts for CR calculated that an adult eating just one serving of canned green beans from the sample would get about 80 times more BPA than the recommended daily upper limit.
Vegetables don’t come with BPA in them naturally. The compound is presumably leaching out of the linings of metal cans. Cans are usually lined with an epoxy that uses BPA in its makeup. Although some soft drink and beer cans may also have such linings, CR did not report testing the beverages.
Many people are aware of a controversy over BPA in hard plastic (polycarbonate) water and baby bottles. Infants are more sensitive to environmental exposures, and there is concern that being exposed to synthetic estrogen at an early age could lead to developmental problems. Canada banned BPA-containing baby bottles from the market, and many manufacturers in the U.S. now offer BPA-free alternatives.
In animals, even low-level exposure to BPA in utero or early infancy can lead to genital abnormalities. It makes female animals more likely to develop breast cancer (Reproductive Toxicology, Nov/Dec., 2008) and male animals more susceptible to prostate cancer (Basic and Clinical Pharmacology and Toxicology, Feb., 2008). Exposed animals may also have higher cholesterol levels and are more likely to be fat and to develop diabetes (Journal of Atherosclerosis and Thrombosis, Vol. 14, No. 5, 2007).
Deliberately exposing human babies to this hormone disruptor to see what effects it has would be unethical. And yet we are all exposed. About 92 percent of Americans who have been tested have measurable amounts of BPA in their urine.
Although some skeptics have expressed doubt that this has relevance for health, a recent report from China demonstrates that adult men exposed to relatively high levels of BPA on the job were four times more likely than non-exposed workers to report sexual difficulties such as lowered libido, reduced satisfaction and erectile dysfunction (Human Reproduction, online Nov. 10, 2009).
The Chinese research is very recent, but we have been tracking reports of trouble with BPA for some time. It is possible to reduce levels of BPA in food packaging. The Japanese removed it from cans several years ago and found that BPA levels in people dropped dramatically. Choosing foods and beverages carefully may reduce our exposure as well.
