Animal studies in recent years raise the possibility that prenatal exposure to minuscule amounts of common chemicals — found in everything from baby bottles to toys — could predispose a body to a life of weight gain. The chemicals, known as endocrine disrupters, mimic natural hormones that help regulate, for example, how many fat cells a body makes and how much fat to store in them.
Thousands of chemicals have come on the market in the past 30 years, and some of them are showing up in people’s bodies in low levels. Scientists studying obesity are focusing on endocrine disrupters — which have already been linked to reproductive problems in animals and humans — because they have become so common in the environment and are known to affect fat cells.
One key researcher in the field, Bruce Blumberg of the University of California, Irvine, has even coined a new word for chemicals that can make you fat: Obesogens.
A recent US Centers for Disease Control and Prevention study found that about 93 percent of the US population had bisphenol A, a chemical that can be found in canned goods and in hard, clear plastic items such as baby bottles and hiking containers, in their body. A study at the University of Missouri-Columbia showed that mice fed bisphenol A during early development — at lower amounts than what would have resulted in the levels found in most people in the CDC study — become markedly more obese as adults than those that weren’t fed the chemical. Tufts University scientists observed similar phenomenon in rats.
For those who don’t want to wait until all the evidence is in, there is another question: How to avoid these chemicals now?
“It can be difficult,” said Felix Grun, assistant researcher in the department of developmental and cell biology at the University of California who works with Blumberg. To minimize exposure to bisphenol A, Grun said people can avoid buying plastics with the recycling number 7 marked on the bottom, but similar types of chemicals abound in other products, too. “These compounds are everywhere, the carpet fibers, the PVC piping, etc,” he said.