Obesity and the environment

Obesity and the environment aims to look at the different environmental factors that have been determined by researchers to cause and perpetuate obesity.

Studies have shown that obesity has become increasingly prevalent in both people and animals such as pets and laboratory animals. There have been no linkages found between this obesity trend and diet and exercise. According to Professor Robert H. Lustig from the University of California, San Francisco, “[E]ven those at the lower end of the body mass index (BMI) curve are gaining weight. Whatever is happening is happening to everyone, suggesting an environmental trigger.” The theory of environmental obesogens proposes a different causal facet to obesity – that lifetime exposure to xenobiotic chemicals may change the body’s metabolic system. Chemical obesogens are molecules that do not properly regulate lipid metabolism in the body and could therefore promote obesity. Data is scarce, but some in-vitro studies have found this model could be an accurate predictor of future obesity. A study suggested that smoking before and during pregnancy, for example, increases the risk of obesity twofold in children of school age.

Many chemicals that are known or suspected to be obesogens are endocrine disruptors. These obesogens are present in common-use products. In a University at Albany, State University of New York study, organotins were found in a designer handbag, vinyl blinds, wallpaper, tile, and vacuum cleaner dust collected from 20 houses.Phthalates, which have also been linked to obesity, are present in many PVC items in addition to scented items like fresheners, laundry products, and personal care products. Bisphenol A (BPA), is one known environmental obesogen that reduces overall number of fat cells, but makes remaining fat cells larger. Effects of obesogens in animals are the same effects researchers see later in life for low-birth weight babies – glucose intolerance and more abdominal fat. The study concludes that obesogens change an individual’s metabolic set points for gaining weight.

What little research has been conducted on the relationship between chemical exposure and body mass index points to obesogens as a likely contributor to the obesity epidemic. Some endocrine disrupting chemicals (EDCs) belong to this class of compounds. Bruce Blumberg, a professor of developmental and cell biology at UC Irvine, has found compelling evidence that exposure to the chemical Tributyltin (TBT), a compound used in pesticides, can trigger fat cell creation. As several cases have confirmed, many farm workers in America have unwillingly or unknowingly worked in fields that had been recently sprayed with TBT and other dangerous chemicals. Among a wide variety of health risks, farm workers may bear a disproportionate risk of exposure to such obesogens. While legislation has been enacted to require a minimum amount of time to pass before workers enter sprayed fields, the lack of legal and political power of many farm workers combined with the fact that enforcing such laws can be difficult, makes exposure to obesogens a possible threat to the livelihood of many farm workers.

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