When we think of the drivers behind America’s obesity epidemic, sugar-laden beverages, such as soda and sports drinks, and too little exercise might come to mind. Efforts like First Lady Michelle Obama’s “Let’s Move” campaign are being implemented nationwide to help rein in the childhood obesity rate, which has tripled over the past three decades.
But parents beware – a recent study in the Journal of the American Medical Association adds another potential offender to the list: the chemical Bisphenol A, or BPA, commonly found in canned food, bottled liquids, and other consumer products. Researchers found that children and teens with higher concentrations of BPA in their body were more likely to be obese.
We asked Dr. Emily Barrett, a scientist (and parent!) who studies the influence of various chemicals on development, to shed some light on BPA and what the findings mean for moms and dads trying to raise healthy kids.
Scripts: Studies show that most of kids’ exposure to BPA is through food. Are we exposed mainly through canned goods and other packaged foods? What about fresh fruits and vegetables?
Barrett: Food does appear to be a main source of exposure to BPA, and several studies have now shown that BPA levels drop when individuals avoid processed foods. Many studies suggest that cans are a major source; the linings are often made with an epoxy resin containing BPA.
But BPA is probably lurking in a lot of other foods as well, since the food can be exposed to the chemical during processing. And unfortunately, environmental chemicals like BPA might even be found in foods that we typically think of as unprocessed, like fresh meats and dairy. That said, fresh fruits and vegetables are unlikely to be a major source of BPA and remain a smart choice.
Scripts: Why might higher levels of BPA be tied to obesity in kids and teens? And why was a link only found among whites – not blacks or Hispanics?
Barrett: At this point, we don’t understand much about the mechanisms by which current BPA levels might be connected with obesity, as most of the research so far has focused on prenatal exposures. One possibility, though, is that kids who are obese eat greater quantities of foods that are high in BPA, such as fast food, than slimmer kids.
Another possibility is that higher consumption of BPA might actually change metabolism in some way that promotes obesity.
Still, another possibility is that BPA is stored in and released from fat tissue, and since obese kids have more fat, the levels they excrete will be higher. Further study is needed to better understand these possibilities.
As far as racial differences in the relationship, it may simply be due to different eating patterns and behaviors across cultures. It could also be due to genetic or metabolic differences, but again, more research is needed.
Scripts: What is your advice for parents raising kids and teens? Should they work hard to avoid foods containing BPA? Or should they focus more on common sense recommendations, like eating more fruits and vegetables and getting more exercise?
Barrett: The good news is that by following already tried-and-true recommendations, you’ll likely avoid foods that contain high levels of BPA. We know that highly processed foods tend to be bad for you nutritionally, and those foods are also more likely to have high levels of BPA. So, if you’re encouraging your kids to eat fresh, minimally processed foods, you’re already doing the right thing.
Parents who want to go a step further may think about reducing their use of canned goods – fresh and frozen alternatives are likely to be better for you, plus they taste better, too. They may also want to check their food packaging, plastic food storage containers, and water bottles; those marked with 1, 2, 4, 5, and 6 recycling codes are unlikely to contain BPA. Those marked with 3 and 7 might. One final tip: Avoid putting plastics in the microwave, as they might release toxins under high heat.
Up to 80 percent of children who are obese remain overweight as adults, according to the National Institutes of Health (NIH). Learn more about child obesity in URMC’s health encyclopedia, linked here.
Emily Barrett, Ph.D., is an assistant professor in the Department of Obstetrics and Gynecology at URMC.
Thanks for your comments, Michelle. We did try to be careful, selecting words like “potential,” “possible” and “might.” Dr. Barrett’s response in the second question also makes it clear that we don’t understand the association in enough detail to say that one causes the other (in either direction).
That said, you raise a fair point; we appreciate your concerns about what word choices might imply. As you mentioned, it is indeed difficult to walk a line between writing compelling content that draw readers in, and using language that doesn’t misrepresent the facts. We appreciate you writing and keeping us on our toes as we strive be be engaging and balanced all at once!
As a parent, I was triggered to read this news release and the JAMA article it was based on; as a scientist, I feel obliged to comment on the effects of the language used in the news release. The word “blame” in the title implies more of a causal relationship between BPA and obesity than the study actually indicates. There is a *link* between BPA levels and obesity, but the causal relationship could be the other way around (i.e. that obesity causes higher BPA levels) or simply an association via a 3rd independent factor (i.e. eating processed foods causes both obesity and higher BPA levels). The title, while eye-catching, creates subconscious bias that makes a person less likely to be receptive to the alternative, nonalarming explanations for the finding presented in the middle of the article. Cautioning parents to “beware” based on this study implies a level of scientific evidence of causation that does not exist. Epidemiologic associations need to be presented in a balanced way, so that the lay public does not walk away with unwarranted anxiety based on one particular explanation.