Could Obesity Epidemic's Cause be Plastic Toxins?

DATA DRIVEN VIEWPOINT: Could it be that American's are being systemically poisoned by BPA exposure from plastic?  When we look around as see so many overweight people, are we observing the evidence that we are being poisoned by BPA and other environmental toxins?

Can BPA Make You Fat?

—By Tom Philpott

http://www.motherjones.com/tom-philpott/2012/05/bpa-fat-obese-badge-cans

An Excerpt from Mother Jones: 

One of the most common of these obesogens is bisphenol A, commonly known as BPA, the ubiquitous chemical found in everything from the lining of cans to the paper that most receipts are printed on. Research suggest that it's in the urine of upwards of 90 percent of Americans—evidently at levels high enough to cause harm.

According to University of Missouri biologist and well-known BPA researcher Frederick vom Saal, it also affects how the body deals with fat. "BPA reduces the number of fat cells but programs them to incorporate more fat, so there are fewer but very large fat cells," vom Saal recently told Environmental Health Perspectives. "BPA exposure is producing in animals the kind of outcomes that we see in humans born light at birth: an increase in abdominal fat and glucose intolerance."

A study released last week by University of California-Irvine researchers further implicates BPA in the obesity problem—and raises even greater suspicion about a related compound called bisphenol A diglycidyl ether, a combination of BPA and something called epichlorohydrin, thisWorld Health Organization report explains. It's through BADGE that BPA makes it into in food can linings. UC-Irvine biologist Bruce Blumberg, who coauthored the study, explained to me in an email that the BPA that ends up in our food through can linings gets there when BADGE breaks down into its components.

Ubiquitous bisphenol A (BPA) linked to adult obesity, insulin resistance.

From Environmental Health News

http://www.environmentalhealthnews.org/ehs/newscience/2011/12/2011-1227-bpa-adult-obesity-insulin-resistance/

Jan 04, 2012

Wang, T, M Li, B Chen, M Xu, Y Xu, Y Huang, J Lu, Y Chen, W Wang, X Li, Y Liu, Y Bi, S Lai and G Ning. 2011. Urinary Bisphenol A (BPA) concentration associates with obesity and insulin resistance. The Journal of Clinical Endocrinology and Metabolism http://dx.doi.org/10.1210/jc.2011-1989.
Synopsis by Steven Neese

High urinary levels of bisphenol A in older adults are associated with increased weight and waist size, both indicators of obesity that can lead to serious illness and disease.

Researchers in China have found that adults over the age of 40 with higher levels of bisphenol A (BPA) in their urine tend to be obese, have more abdominal fat and be insulin resistant. These metabolic disorders can lead to further and more harmful health problems, such as high blood pressure, diabetes and heart disease.

Since BPA exposure is widespread – almost all people in the United States carry it in their bodies – the study's results highlight a potentially significant health risk from exposure to the contaminant.

BPA is a high-production chemical used in the manufacture of polycarbonate plastics, in epoxy resin linings of food cans and in some thermal receipt paper. The chemical can contaminate food and drink and enter the body through diet. BPA can also be absorbed through the skin or breathed in.

Prior epidemiological studies, published in the Journal of the American Medical Association and the journal PLoS One, have revealed links between BPA and metabolic disorders, consistent with this new research.

Previous lab-based studies correlate BPA to an increase in fat cells and increases in insulin hormone levels. These, in turn, can lead to hyperinsulinemia and insulin resistance and – perhaps – obesity. Exposures to this chemical in rodents during prenatal periods also alter the development of brain regions associated with food intake and metabolism. Hence the animal studies add to the plausibility of these new results from China.

In the study, BPA levels were measured in 3,390 adults older than 40 from the Songnan Community, Shanghai, China. Sociodemographic, medical and lifestyle backgrounds were collected from each person. Glucose and insulin levels were also measured.

Body mass indexes (BMI, the weight divided by height) were calculated for each person. "Overweight" was considered as a BMI from 24 to 28 while a BMI over 28 was considered "obese." Abdominal obesity was defined as a waist circumference more than 35 inches in men and 33.5 inches in women.

BPA was measured in a morning urine sample. The BPA levels were classified into groups by increasing concentration levels (from low to high), and the groups were compared. These levels where well within those typically seen in the United States.

The highest BPA levels were associated with both an obese BMI and waist circumference and higher concentrations of insulin in the blood. Overall, the younger men (average age of 59) in the study tended to have the highest levels of this chemical in their urine.

In participants with a BMI under 24, the prevalence of insulin resistance was increased by 94 percent in groups with the highest levels of this contaminant – an increase more prominent than in the obese BMI groups.

This study is limited by the fact that the relationship is based on a single sampling point of BPA and causality cannot be determined by the study's design – the researchers used a cross-sectional approach.

This study suggests that BPA levels in adults represent a health risk because they are related to obesity and related health problems.