The controversial chemical Bisphenol A (BPA) is under fire again as a new study links it to obesity in kids. BPA is used in the manufacturing of liners in metal food and beverage cans and in some plastic containers. Previous studies have suggested that it can affect hormone activity in people, and the FDA has banned its use in baby bottles and sippy cups. The FDA has not issued a full ban on using BPAs in other products stating that there is no evidence that very low levels of human exposure to the chemical through diet is unsafe. However, they have said they will continue to study the issue.
In the new study, researchers report that children with the highest levels of BPA in their urine were more than twice as likely to be obese than children who had the lowest levels.
The study does not proclaim that BPAs cause obesity in children, only that there is a link.
It demonstrates the need for a broader paradigm in the way we think about childhood obesity, says researcher Leonardo Trasande, MD. We often think of it as a byproduct of an unhealthy diet and lack of physical activity, but environmental exposures including chemicals may play a role, too.
Trasande and his colleagues analyzed data from a nationwide health and nutrition survey conducted between 2003 and 2008. Close to 3,000 kids age six to 19 were weighed, measured and had their urine tested for BPA. They also answered a range of diet and lifestyle questions.
In total, about one-third of the kids were overweight and 18 percent were obese.
The average kid had close to three nanograms - three billionths of a gram - of BPA in every milliliter of urine.
The researchers found that just over 10 percent of kids with the lowest BPA levels were obese, compared to 22 percent of those with the highest BPA, according to results published Tuesday in the Journal of the American Medical Association. That was after taking into account how much kids ate overall, as well as their age, race and gender.
Trasande said he was struck by the strength of that link. But it still doesn't mean extra BPA in kids' diets was responsible for their extra pounds.
Trasande offered a couple of other theories on why obese children may have more BPAs in their urine than their thinner study participants.
"Obese children could ingest food that has higher BPA content - it could be what we call reverse causation," he said. Or, "They could have higher BPA stores in their bodies and release more BPA. Those are both very plausible explanations."
If you have concerns about your children, or other family members ingesting BPAs, you can use fresh or frozen vegetables (instead of canned), avoid polycarbonate plastics (thick and transparent plastic), metal water bottles (use stainless steel bottles without a liner), microwavable meals in their plastic containers (empty food onto plate or glass container).
The proven contributor to obesity in kids and adults is a diet high in calories and low in physical activity. BPAs may or may not add to the problem, but reducing bad fats and nutrition-free calories in your diet, while increasing your exercise, can most definitely help correct any non-medical related obesity problem.