The ongoing debate over plastic has been a hot topic for the past year. Last week I shared that BPA is not just in plastics but can also be found in metal-based food and beverage cans. A common question came up in the comments asking about the health risks of BPA so I thought it would be a good idea to follow up and provide a basic overview of the history and possible risks of BPA.

Bisphenol A was first synthesized by chemists in 1891. It was used in Germany in the 1930's because of its chemical structure similarities to estrogen. During the 1940's and 1950's, BPA became popular with the manufacture of a hard plastic known as polycarbonate as well as part of an epoxy resin used in the linings of metal food cans and other packaged products. Although it was well known that BPA leached out of plastic after manufacturing, it was used freely without any requirement to prove its safety. Interestingly, the first U.S. law to regulate industrial chemicals was not passed until 1976 when Congress passed the Toxic Substances Control Act. Up until this point BPA had been widely used for twenty to thirty years and although it failed to pass the new safety controls, it was one of 62,000 chemicals that were presumed safe and grandfathered in for continued use by the EPA. In 1982 The National Toxicology Program (NTP) found the lowest adverse effect level for BPA to be 50 milligrams per kilogram of body weight per day (50 mg/kg/d) and this information provided the basis for the establishment of EPA safety standards in 1988. Although they established reference doses much lower than the previous findings, twenty years of studies revealed toxic levels of BPA with an average intake as low as 2ug/kg/d but the standards continued and were reaffirmed in 1993.

On March 13, 1996 the FDA made their first assessment related to BPA exposure in Americans in which a memorandum from technical staff revealed that adults were exposed to 11 ug of BPA daily through contaminated canned food and infants were exposed to 7 ug/day. One year later in March of 1997 a scientist at the University of Missouri-Columbia found that low levels of BPA exposure were harmful to the prostate. Over the next eleven years, more than 100 study publications revealed risks from low dose BPA toxicity and breast and prostate related negative outcomes. Early puberty and behavioral problems were also linked to toxic levels that are 25 times lower than the EPA's established safe dose. In 1997, BPA leaching from canned infant formula was identified and in 1999 BPA was found to leach from plastic baby bottles however, the FDA continued to hold to their position that it was still a safe chemical to use. A study in 1999 revealed concern with early puberty and BPA exposure in girls and a 2002 Italian study raised concern regarding a link between brain and behavioral effects and BPA exposure while Japanese scientists found an association with BPA and polycystic ovary syndrome, which has become a leading cause of infertility. In 2003 the NIH nominated BPA as a reproductive and developmental toxin for further evaluation by the Center for the Evaluation of Risk to Human Reproduction (CERHR) and between that time and March of 2007 there were many less than straight forward committees formed and reports offered as well as conflicts of interest identified. In March 2007, a broad study of canned foods revealed widespread high exposure to BPA since the chemicals leach from the metal food can linings. The highest concentrations of BPA were found in canned soups, pastas, and infant formulas. The report highlighted that Americans are exposed to harmful levels of BPA at levels well above those found to be harmful in laboratory studies. In September of 2008 the NIH National Toxicology Program declared risks exist from BPA that may affect human development, cause early puberty, prostate effects, risks of breast cancer and behavioral impacts when exposed early in life.

The Bottom Line

Today, BPA is in the top two percent of high-production-volume chemicals in the U.S.. It is readily used in polycarbonate plastics that have a "7" with their triangular recycle symbol as well as in the epoxy resin liners of many cans and water storage tanks. However, it is also in thousands of other products that come into daily human contact such as compact discs, eyeglasses, thermal paper, polycarbonate water pipes, medical devices, and dental sealants. The Centers for Disease Control and Preventions scientists estimate that more than 92 percent of Americans have BPA in their bodies with the highest levels typically found in children. Over the last few decades, we have well documented increases in processed foods, increased childhood obesity and health concerns, early onset of puberty, increased breast and prostate cancer rates as well as more food allergies and cases of hyperactivity disorders and autism. (Edit to remove opinion)

There is more and more focus on eating "clean" and meeting your nutrient needs from whole food and from-scratch cooking sources these days. This approach helps not only to limit sodium and preservatives in the diet but is also helpful when trying to reduce your family's exposure to BPA. Each person will have to take a closer look at their typical intake to see what role if any BPA's may have in their diet and what changes if any are in order.

Is there any information here that surprised you? Do you think there is factual reason to be concerned with BPA exposure for you and your family? Do you still have questions?