According to the Boston Globe, bisphenol A levels lower than those found in 93% of people led to obesity in mice:
Thousands of chemicals have come on the market in the past 30 years, and some of them are showing up in people’s bodies in low levels. Scientists studying obesity are focusing on endocrine disrupters – which have already been linked to reproductive problems in animals and humans – because they have become so common in the environment and are known to affect fat cells.
…A recent US Centers for Disease Control and Prevention study found that about 93 percent of the US population had bisphenol A, a chemical that can be found in canned goods and in hard, clear plastic items such as baby bottles and hiking containers, in their body. A study at the University of Missouri-Columbia showed that mice fed bisphenol A during early development – at lower amounts than what would have resulted in the levels found in most people in the CDC study – become markedly more obese as adults than those that weren’t fed the chemical. Tufts University scientists observed similar phenomenon in rats.
….Growing up with more fat cells isn’t necessarily a problem if you are running around a lot, says Pete Myers, chief scientist for Environmental Health Sciences, which publishes the online journal Environmental Health News. But in a world where exercise is down and poor diets abound, it could exacerbate a weight problem.
Vom Saal says as people become adults, they may be able to shake off the weight with extreme diet and exercise, but it won’t be easy. “It is a very intractable thing to change,” he said.
Scientists who study obesity’s link to chemicals say the research is still in its infancy. Among the many unanswered questions that remain: How do the changes happen? What about the combined impact of exposure to many chemicals? Are humans affected by the chemicals the same way as animals?
To the extent there is a bisphenol A effect or an effect of other environmental ‘obesogens’, it’s probably not as a simple as “lots of X, lots of obesity.” Some people are probably genetically more predisposed to sensitivity to these environmental compounds than others–otherwise most of us would be obese. Definitely worth more investigation though.
An aside: would it kill newspapers to put citation information about the articles, at least on the internet version of the story? I hate not being able to quickly hunt the primary literature down.