Every year, manufacturers churn out 8 billion tons of bisphenol A, or BPA, a petroleum-based chemical, for use in things like polycarbonate (#7) plastic water bottles and the epoxy liner of most food and drink cans. It's even been found in cigarette filters and in many thermal cash-register receipts. Because people routinely toss these thermal receipts in with paper recycling—a big no-no—many recycled papers are also contaminated with BPA.
Previously believed to pose a threat only in large doses, research over the past several years has shown that BPA is also dangerous in tiny doses. That's because even at miniscule levels, the chemical acts like a fake hormone when it enters your body, throwing your system's normal hormonal responses upside down.
Today, known BPA health effects include links to serious health concerns like fertility problems, breast cancer, behavioral disorders, and heart problems. In fact, Environmental Working Group, a public-health advocacy group, recently name BPA one of the 12 worst chemicals in your home.
The problem is traditional toxicology testing wasn't catching these links. So in 2007, a group of 38 researchers wrote what is known as the Chapel Hill Expert Panel Consensus Statement on BPA. The scientists wrote five separate review articles summarizing what was known at the time about BPA and its link to cancer, its effects on molecular mechanisms in cultured cells, detectable levels in humans and their exposure sources, and the chemical's effect on wildlife and laboratory animals. Some even looked at the effects of low doses, doses below those tested in traditional toxicology testing.
In a one-of-a-kind statement, researchers also outlined what they didn't definitively know about BPA, something that likely shaped BPA research conducted over the past five years. "We found that many of these areas that had limited information in 2007 had significantly more information available in 2013, suggesting that those 'data gaps' identified in 2007 were helpful in steering scientific studies—and were tackled by numerous laboratories," explains Laura Vandenberg, PhD, assistant professor of environmental health science at the University of Massachusetts–Amherst. She was involved with the landmark 2007 statement.
Since their 2007 report, the researchers involved with the Chapel Hill statement on BPA have analyzed more than 400 new studies investigating BPA's impact on humans, lab animals, and cell cultures. Using state-of-the-art tools, scientists are increasingly able to study potential health effects of ultra-low doses of BPA, not just those of large doses given in traditional toxicology testing. In updating their review, the scientists took a new approach, Vandenberg explained, asking if they saw similar effects in cultured cells, laboratory animals, and in humans.
"Overwhelmingly, the data suggest that BPA has effects at low doses on cells, animals, and human populations," she explains. "Using this approach, we could clearly see that there were patterns visible across multiple levels of biological organization… what we see in cells could predict what we would see in animals. Or what we see in animals could predict what was observed in human populations."
For example, scientists saw that BPA affects eggs and ovarian cells both in cultures and in animals. And it appears to have some relationship with in vitro fertilization outcomes in women trying to get pregnant.
Read More: 5 Weird Things BPA Is Doing to Your Body
Looking at tiny doses—ones often comparable to the exposures we experience every day—also seems to paint a picture of BPA affecting healthy prostates in men, increased difficulty conceiving in women, abnormal breast development, and even changes in the brain and metabolism.
And although BPA is found inside virtually all of us because of our constant exposure, it appears there's really no less-harmful stage of life to come into contact with the chemical. Studies have ID'd negative health effects when exposure occurs during prenatal development, early childhood, and even adulthood.
When looking at low-dose BPA exposure's impacts on reproduction alone, researchers found harmful effects from amounts 10 to 40 times lower than levels found to be harmful in toxicology testing. Other negative health impacts of small amounts of BPA include polycystic ovarian syndrome, weakened immune systems, and behavioral problems.
To protect yourself from BPA, support lawmakers who back true chemical reform. Avoid eating and drinking out of plastic containers, and instead choose glass, food-grade stainless steel, or ceramic. Say no to frivolous receipts, and when you must keep receipts, store them in a box—not at the bottom of your purse. And choose fresh or frozen food instead of canned versions. Most canned food contains BPA. Be wary of BPA-free plastics and cans, too. Many contain BPS, a BPA replacement that has been found to be just as toxic a hormone disruptor as BPA.