Daily News Archive
From December 14, 2006                                                                                                        

Persistent Pollutants Linked To Obesity
(Beyond Pesticides, December 14, 2006) A study published in the September 2006 Molecular Endocrinology has linked a class of environmental contaminants, organotins, with excess weight gain and fat cell aberrations, complicating the debate over what factors are contributing to an international obesity epidemic. Organotins are ingredients in many household products, including pesticides, and are persistent compounds found in low concentrations in most humans and animals.

U.S. and Japanese scientists studied organotins, found in boat hull antifouling paints, pesticides, wood preservatives, textiles and plastics, primarily because of their endocrine-disrupting effects, which have been increasingly implicated as contributing to weight gain and obesity. Previous studies have documented other negative environmental and health effects, including masculinization in some fish and liver damage in some mammals.

In assessing how organotins affect weight gain, scientists studied their affects on mice and frogs in vitro and in vivo. Several organotins were found to disrupt the normal function of receptors related to fat cell differentiation. Exposure in neonatal mice led to significant disruption of signaling pathways and aberrant fat cell formation at several sites, including the liver, testis, and epididymis (where sperm are stored and become mature).

In utero exposure in mice also led to greater accumulation of fat in several sites after the mice were born. Further, although the birth weight of mouse pups exposed in utero tended to be normal, at age ten weeks the fat content in their epididymis was 20% higher than normal. Aberrant development of fat tissues around the gonads in both males and females also occurred in the frogs. These findings fit with research by other scientists showing that humans can be underweight at birth, but can quickly become overweight, possibly because their fat cell content or function is abnormal.

Obesity around the world has become increasingly prevalent in the past 30 years, with the United States leading the epidemic. Excess weight is associated with numerous serious health problems, including heart disease, Type 2 diabetes, high blood pressure, and some cancers. Though traditionally understood as the result of healthy diet and exercise habits, this study of organotins indicates that prevention of obesity may also require avoiding exposure to environmental contaminants over the course of a lifetime, even prior to conception. Human exposure to organotins typically occurs through consumption of contaminated foods and contact with treated materials.

Source: Environmental Health Perspectives