More than one million pounds of bisphenol A, or BPA, are released into the environment each year, but scientists are beginning to find that it could take just a tiny amount to create strange and lasting health problems. Embedded in some plastics, as a protective lining inside most canned foods and drinks and as a coating on cash register receipts, BPA is in so many everyday products that's it's inside of most of us, too. Researchers have detected the industrial chemical in the blood and urine of most Americans; it even turns up in amniotic fluid and placentas, meaning fetuses are exposed before birth.
Yet, in an increasing number of studies, BPA is being found to be a reproductive, developmental and systemic toxicant. Much of the focus has been on the chemical's ability to interfere with levels of estrogen in the body, but scientists are discovering that its effects spread far beyond hormonal systems, resulting in health problems that are downright bizarre. Here's how scientists say BPA could be affecting our bodies:
In 2013, French researchers published a study showing that daily low doses of BPA could be damaging tooth enamel. A research team from the Université Paris-Diderot found that within 30 days, newborn rats exposed to small amounts of BPA daily experienced molar incisor hypo-mineralization, a condition that causes hypersensitivity and increases the risk of developing cavities. Roughly 18 percent of children between the ages of 6 and 8 experience this unhealthy change that leads to white marks and brittle enamel. The researchers note that children's teeth form in the first year of life—a period when human bodies are often most sensitive to BPA.
According to study co-author Sylvie Babajko, the latest author of this article, "Insofar as BPA has the same mechanism of action in rats as in men, it could also be a causal agent of MIH. Therefore, teeth could be used as early markers of exposure to endocrine disruptors acting in the same way as BPA and so could help in early detection of serious pathologies that would otherwise have occurred several years later."
A 2011 animal study published in the journal PLOS One found BPA overrode the female body's natural heartbeat signaling, causing arrhythmia—erratic beating that could cause sudden cardiac death. Long believed to cause heart disease, this study provided insight into how BPA impacts the heart.
Low Sex Drive
A May 2013 study led by Chinese researchers and published in the journal Fertility and Sterility found chronic exposure to BPA leads to lower testosterone levels in men. BPA, which acts similarly to a synthetic form of estrogen, can throw off men's sex hormones levels, which can sink their sex drive. Earlier evidence came in 2010, when the results of a 5-year study in humans confirmed that high levels of BPA in the urine correlated with low sperm counts and poor sperm quality.
Studies in the lab find that BPA has the ability to accelerate fat-cell differentiation, disrupt pancreatic functioning, and cause insulin resistance, leading to obesity problems. A recent Chinese study published in The Journal of Clinical Endocrinology & Metabolism found adults with the highest level of BPA were 50 percent more likely to be fatter, with a body mass index in the overweight or obese category. Study participants with high BPA levels were also 28 percent more likely to harbor dangerous abdominal fat. "This human study, together with the previous studies that show relationships between BPA exposures and obesity or other metabolic endpoints, are concerning because they suggest that there are no 'safe' populations—even adults may be affected by low level exposures to this chemical," BPA expert Laura N. Vandenberg, PhD, postdoctoral fellow of regenerative and developmental biology at Tufts University, told Rodale News when the study was released.
The canned food of today could impact the health of your great-great grandchildren! A recent study published in the journal Endocrinology studied the trans-generational effects of BPA on mice. Compared to a mother mouse who ate BPA-free food, the who ate BPA-laced food gave birth to less social, more isolated pups. Some of the behavioral changes they observed in mice while studying the different generations exposed to BPA included symptoms associated with autism and attention-deficit hyperactivitiy disorder. Genetically speaking, BPA exposure changed how estrogen receptors switched on and off.
While consumer pressure has led to bans on BPA in baby bottles and canned baby formula manufactured in the U.S., the chemical is still used in things like polycarbonate water bottles, plastic utensils, and other food containers. France is taking a more hardline approach, banning BPA in all food containers by July 2015. Still, the U.S. has made no such move to prevent what scientists consider dangerous, low-dose exposures.
• Avoid plastic food and drink containers—use food-grade stainless steel or glass instead.
• Say no to trivial receipts. Experiments show it transfers from the paper and through your skin. When you need a receipt, store it in an envelope, not in your wallet or in the bottom of your purse where you'll have repeated contact with it.
• Opt for fresh and/or frozen vegetables instead of canned.
• Be skeptical of BPA-free claims. A 2013 study found a common BPA replacement, BPS, also features hormone-disrupting qualities.
Published on: July 15, 2013
Updated on: August 20, 2013