Human studies are limited. However, data from 3,967 adult U.S. men and women showed an association between higher BPA levels and obesity, regardless of race or gender, according to a study published in July 2012. The same association was found in Chinese adults in a study published in February 2012.
In addition, baby rats exposed to BPA had increased body weight even though they were fed a normal diet, according to an August 2011 study. In the same study, the results of obesity were exacerbated when the rats were fed a high-fat diet and exposed to BPA.
The jury is still out on how a chemical like BPA would spur obesity, Newbold said.
“There are a lot of hypotheses floating around,” Newbold said. “It’s possible that it (BPA) alters neural development, which has been shown in rodents, and it increases their craving for sugar.”
Most research on environmental chemical-induced obesity is focused on altered brain development, Newbold said.
“We’re just now really digging into this stuff,” she said.
It is difficult to investigate effects such as obesity because BPA doesn’t stay in the body long. Since exposure comes from foods, however, BPA is continuously present in most people’s bodies, Trasande said.
The new study found that compounds similar to BPA – other phenols, often in products such as sunscreens or soaps – were not linked to obesity in the children. They also controlled for activity level, calorie intake, tobacco exposure, race and education levels of whomever takes care of the child.
About 12.5 million, or 17 percent, of U.S. children are obese, which can lead to high blood pressure, diabetes and breathing problems. Obese children also are more likely to become obese adults.
“When a child becomes obese, it’s a life sentence,” vom Saal said. “It’s not something the medical establishment has found a way to treat.”
Trasande pointed out that 1,000 to 3,000 new chemicals have been produced every year since the 1970s, and at the same time we’ve seen a rise in childhood obesity. But he was quick to point out that there are “definitely limits to how much you can say to that.”
Chemical industry representatives remain skeptical.
"Due to inherent, fundamental limitations in this study, it is incapable of establishing any meaningful connection between BPA and obesity," said Hentges of the chemical industry group. "In particular, the study measures BPA exposure only after obesity has developed, which provides no information on what caused obesity to develop," he said.
Jennifer Wolstenhome, a University of Virginia postdoctoral fellow who studies endocrine disruption, said the study was strong, but noted that one limitation is the age range, which "spanned critical windows of development," including puberty."
Since children’s bodies undergo many changes during those years, it could skew the results. For example, the chemical may affect children in different ways during or after puberty, when hormones change.
Trasande said he’d like to further this research by doing a longer term, population-based study on BPA looking at exposures even earlier in life and the potential for obesity, since susceptibility for infants is high.
“Poor diet and activity level certainly matter, but we need to be looking at environmental chemicals’ role in obesity too,” Trasande said. “Our study suggests we should reconsider the uses of BPA in the context of these new findings.”
See what we're tweeting about
8 Comments
Add CommentWait so this study dealt with children after they became obese, and they suggest that the majority of exposure comes from diet, so if you eat more you have a higher exposure to BPA? Am I missing anything here?
Reply | Report Abuse | Link to thisMy thought exactly - perhaps children who eat more (especially expensively packaged junk food) become obese!
Reply | Report Abuse | Link to thisThis most straightforward possible causal factor doesn't seem to have been considered...
Dear Fellow Readers:
Reply | Report Abuse | Link to thisHere is a link to the National Public Radio presentation on this subject with a very different conclusion.
http://www.npr.org/blogs/health/2012/09/18/161340024/link-between-bpa-and-childhood-obesity-is-unclear
Thank You.
BPA, a trace chemical in some plastics, is insignificant in its effects compared to the effects of trace chemicals in sugar and salt. We consume large amounts of sugar and salt and hardly any plastic, but fear mongers want us to imagine that BPA is the problem.
Reply | Report Abuse | Link to thisWe should realize that much of the sugar and salt that we consume is not even free of bacteria since it has not been sterilized properly, for example.
We should realize that the main reason that we live so long is because our water is treated with chlorine; it is not because of low BPA in plastic. We need research on real problems instead of minor problems.
Thank you for your link!
Reply | Report Abuse | Link to thisYes - thanks very much for the NPR link.
Reply | Report Abuse | Link to thisIt's refreshing to see some unbiased, in-depth reporting!
This study does not provide sufficient evidence to establish a link between obesity and BPA levels, however, BPA is a documented known toxin. It does not belong in packaging for food.
Reply | Report Abuse | Link to thisIf BPA is not used in food packaging then it will not build up to toxic levels in the bodies of people that are not exposed to it in some other way. A quick check of the Mayo Clinic web site shows that health researchers are moderately concerned about the impact of BPA. There is a direct correlation between the introduction of BPA in the 1960s and the onset of increased sterility and increased obesity in the U.S. population. Correlation is not Causation and so the Mayo Clinic wisely withholds judgement until further research is done.
Reply | Report Abuse | Link to thisThe only people saying it is harmless are the people that make and sell it. Hardly neutral but they may still be correct.