Research links common chemicals to obesity

GENEVA (Reuters) -
Exposure in the womb to common chemicals
used to make everything from plastic bottles to pizza box
liners may program a person to become obese later in life, U.S.
researchers said on Wednesday.

Their studies of mice showed animals exposed to even tiny
amounts of the chemicals during development were fatter when
they grew older compared with mice not exposed to the
compounds, they told the 2008 European Congress on Obesity.

"We are talking about an exposure at very low levels for a
finite time during development," said Jerry Heindel of the U.S.
National Institute of Environmental Health Sciences.

"The fact that it is such a sensitive period, it may be
altering the tissue and making people more susceptible to
obesity."

The World Health Organization estimates some 400 million
people are obese, a problem that raises the risk of conditions
like type 2 diabetes and heart disease.

Previous studies have linked these chemicals -- also found
in water pipes -- to cancer and reproductive problems,
prompting a number of countries and U.S. states to consider
potential bans or limits of the compounds, the researchers
said.

One of the chemicals is called Bisphenol A, found in
polycarbonate plastics. Past research has suggested it leaches
from plastic food and drink containers.

A team at Tufts University in the United States showed that
female mice whose mothers were exposed to this chemical early
in pregnancy gained more weight in adulthood even though they
ate the same amount of food and were as active as other mice.

A similar effect occurred with perfluorooctanoic acid -- a
greaseproofing agent used in products such as microwave popcorn
bags. These animals were unusually small at birth then became
overweight later in life.

"One of the problems we are finding is we don't know where
all these chemicals are," said Suzanne Fenton, a research
biologist at the U.S. Environmental Protection Agency, whose
research focused on perfluorooctanoic acid.

The chemicals appear to disrupt the endocrine system by
altering gene and metabolic function involved in weight gain,
said Bruce Blumberg, a University of California biologist.

The result is the offspring store fat cells more
efficiently, which makes them gain weight, he said. Blumberg
studied tributylin, a chemical used in boat paint, plastic food
wrap and as a fungicide on crops.

The findings suggest some people may be programmed to
obesity before birth and underscore the need to identify
biomarkers scientists can use to identify people at risk, the
researchers said.

"We are calling this an emerging hypothesis," Heindel said.
"Most of the data is in animals and we want to develop some
biomarkers that could be used in humans.

(Editing by Matthew Jones)