We've all heard that the endocrine-disrupting chemical BPA can be harmful, but scientists have now linked exposure in pregnant women to diabetes and weight gain.
The endocrine-disrupting chemical bisphenol A, otherwise known as BPA, has been a nefarious three-letter word ever since we first heard about it nearly ten years ago. At this point, almost 100 studies draw a connection between the apparently ubiquitous substance and negative health outcomes.
Now, some brand new research to be published in the Endocrine Society's journal Endocrinology indicates that BPA exposure during pregnancy is linked to glucose intolerance and beta cell dysfunction up to seven months postpartum. In other words, expecting women are at increased risk for weight gain and diabetes well after birth.
The study observed pregnant mice that were exposed to high, low, and zero levels of BPA. Once the mice had their babies, researchers found that the exposure groups had trouble metabolizing sugar. And the effect worsened over time. What's more, the scientists noted lower levels of insulin secretion in the animals exposed to BPA. Unsurprisingly, the exposed mice were generally heavier than the control ones, and as with most animal studies, researchers believe that outcomes may translate to humans as well.
BPA is prevalent and potentially very harmful
So where did this stuff come from? Michael Green, executive director at the Center for Environmental Health, says that BPA was first developed in the 1930s to help prevent miscarriage but was later abandoned and replaced with the more potent DES, which had to be taken off the market for causing cancer.
These days, more than 96% of Americans have BPA coursing through their systems due to environmental exposure, according to the U.S. Centers for Disease Control and Prevention. And it's a nasty chemical if there ever was one. It effectively mimics, blocks, or disrupts hormones that regulate major bodily functions, including the brain (hyperactivity, aggressiveness, and learning disabilities), reproduction (reproductive organ cancers and diseases, reduced fertility, and impaired libido), the immune system (allergies and asthma), and energy regulation (obesity and diabetes)—the last of which is the focus of the recent study—says Frederick vom Saal, Ph.D., curators' professor in the Division of Biological Sciences at the University of Missouri-Columbia.
Pregnant women should steer clear for their babies and themselves
We frequently think of babies and children when we assess these types of health risks. "Babies' bodies are forming. A wrong signal [from a hormone-mimicking chemical] puts the body on a pathway that cannot be altered back to normal once the damage to a developing system occurs," vom Saal says, adding that effects may be permanent because fetuses and infants lack the developed defense mechanisms that adults have.
While the effect of in-utero BPA exposure has been well documented, this new study appears to be one of the first major efforts to look at what it does to mothers. It illustrates a new potential "window of susceptibility" in pregnant women that doesn't exist outside of pregnancy.
"It is always difficult to translate rodent results to humans," says Angel Nadal, Ph.D., one of the study authors. "But in humans, implications will be that BPA exposure during pregnancy increases mothers' susceptibility to type-2 diabetes and other metabolic disorders later in their life."
Where BPA is found
We know that canned food and beverages, water bottles, and grocery receipts all contain BPA. So where else is BPA lurking?
The answer, unfortunately, is kind of vague. Green indicates that BPA is also common in polycarbonate, which is used in some electronics, sports equipment, and medical devices. While pregnant women may not be able to avoid these items entirely, limiting exposure to CDs, DVDs and screens with polycarbonate films, like cell phones and laptops, is a step in the right direction. Just how commonplace these items are, however, remains unclear.
"There were 15 billion pounds of BPA used in products in 2013," says vom Saal. "[But] industry will not tell us what products contain BPA." Currently, Congress is looking at the outdated Toxic Substance Control Act and hopefully working towards legislation that would give states and federal agencies the power to regulate.
"The problem of endocrine disruptors is that we are not only exposed to BPA, we are exposed to a cocktail of these chemicals that can affect our health, particularly during pregnancy," Nadal says. "Governments must take this problem as a global environmental health issue and they must give global solutions."
But BPA-free may not be any better
Consumer goods manufacturers seem one step ahead, offering BPA-free plastic made from bisphenol S (BPS), but many of the chemicals going into this alternative haven't been tested, so it could be just as bad.
"There are no regulations regarding new chemicals that replace bad chemicals," vom Saal says, citing PBDEs replacing PCBs in the 1970s and BPS replacing BPA these days.
George Bittner, Ph.D., Professor of Neurobiology at the University of Texas-Austin, adds that many BPA-free alternatives simply release other chemicals that similarly have estrogenic activity.
Given the lack of industry accountability, it seems that the responsibility rests, once again, on the shoulders of the consumer when it comes to keeping their families safe from potentially toxic everyday items. So do your own risk assessment, clean out your pantry, and consider using glass or stainless steel containers and frozen foods instead of canned, just to be on the safe side.