(Beyond Pesticides, Feb 21, 2007) Exposure to environmental chemicals found in everyday plastics and pesticides while in the womb may make a person more prone to obesity later in life, new research indicates. Frederick vom Saal, Ph.D, professor of biological sciences at University of Missouri-Columbia’s College of Arts and Science, has found that when fetuses are exposed to endocrine-disrupting chemicals, the way their genes function may be altered to make them more prone to obesity and disease.
Dr. vom Saal presented his research last week at the annual meeting of the American Association for the Advancement of Science (AAAS) in San Francisco. “Perinatal Programming of Obesity: Interaction of Nutrition and Environmental Exposures” is the title of Dr. vom Saalâ€™s AAAS presentation.
“Certain environmental substances called endocrine-disrupting chemicals can change the functioning of a fetusâ€™s genes, altering a babyâ€™s metabolic system and predisposing him or her to obesity,” said Dr. vom Saal. “This individual could eat the same thing and exercise the same amount as someone with a normal metabolic system, but he or she would become obese, while the other person remained thin,” he said.
Obesity puts people at risk for other problems, including cancer, diabetes, cardiovascular disease and hypertension.
Using lab mice, Dr. vom Saal studied the effects of endocrine-disrupting chemicals, including bisphenol-A, which the city of San Francisco has banned in children’s toys starting December 1, 2006. Some polymers used in dental fillings also contain bisphenol-A, and epoxy resins containing bisphenol-A are commonly used to coat the inside of food cans.
Dr. vom Saal found that bisphenol-A and other endocrine-disrupting chemicals cause mice to be born at very low birth weights and then gain abnormally large amounts of weight in a short period of time, more than doubling their body weight in just seven days. Dr. vom Saal followed the mice as they got older and found that they were obese throughout their lives. Low-birth-weight children often show a similar overcompensation after birth, resulting in lifelong obesity.
“The babies are born with a low body weight and a metabolic system thatâ€™s been programmed for starvation. This is called a thrifty phenotype, a system designed to maximize the use of all food taken into the body,” vom Saal said. “The problem comes when the baby isnâ€™t born into a world of starvation, but into a world of fast food restaurants and fatty foods.”
More research must be done to determine which chemicals cause this effect. According to Dr. vom Saal, about 1,000 of the approximately 55,000 human-made chemicals in the world might fall into the category of endocrine disruptors. These chemicals are found in common products, from plastic bottles and containers to pesticides and electronics.
“You inherit genes, but how those genes develop during your very early life also plays an important role in your propensity for obesity and disease. People who have abnormal metabolic systems have to live extremely different lifestyles in order to not be obese because their systems are malfunctioning,” Dr. vom Saal said. “We need to figure out what we can do to understand and prevent this.”
In the past 30 years, the prevalence of both overweight and obese adults and children in the United States has increased sharply, according to the Centers for Disease Control and Prevention, a federal agency. Between the periods of 1976â€“1980 and 2003â€“2004, the prevalence of obesity among adults aged 20â€“74 years doubled, increasing from 15.0 percent to 32.9 percent.
Dr. vom Saalâ€™s research is not the first to link pesticides and obesity. A study done in September 2006 linked a class of environmental contaminants known as organotins with excess weight gain and fat cell aberrations. Organotins are ingredients in many household products, including pesticides, wood preservatives, textiles, and plastics, and are persistent compounds found in low concentrations in most humans and animals.
Source: ENS Newswire