by Playfuls Staff |
18th February 2007
The alpha and omega for a good figure is widely known: lots of exercise and restraint at mealtime.
But overweight is not only a question of discipline, US scientists are [more] saying. The problem could begin already in the mother's womb.
At the annual conference of the American Association for the Advancement of Science (AAAS) in California held this week, several research teams presented explanations for the world-wide obesity epidemic that involve chemicals found in everyday plastics and pesticides.
Animal experiments showed that a mother's exposure to certain chemicals, above all environmental estrogen, can pre-programme a baby to become overweight.
According to the research, exposure to certain chemicals during critical fetal development phases can alter the way their genes function and influence abnormal creation of fat cells and growth after birth, biologist Frederick vom Saal of the University of Missouri said.
"There is now considerable evidence that adult obesity is related to factors that influence growth in utero in both humans and experimental animals," Saal said.
In addition to Saal, experts from the Centres for Disease Control in Atlanta, Georgia, presented evidence from animal experiments to support the theory.
Saal studied the affects in lab mice of bisphenol-A - an estrogen- like substance that has been banned by San Francisco in children's toys. The chemical is also found in plastic baby bottles, some polymer dental fillings and epoxy resins used to coat the insides of cans used in canned food, Saal warned.
Saal found that male and female mice exposed to bisphenol A in the fetal stage had low birth weights but then gained weight abnormally fast, doubling their birth size within seven days. Saal used dosages of bisphenol A that were on a par with or lower than the amount of the chemical a human fetus would be exposed to in an industrial economy.
Individuals exposed to bisphenol A "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 told Environmental News Service.
Bruce Blumberg and colleagues from the University of California in Irvine studied the endocrine-disrupting organotin compound - found above all in preserved shellfish and seafood, fungicides on food crops, as an antifungal in wood treatments, industrial water systems, and textiles.
"It is plausible and provocative to associate the recent increased incidence of obesity with a rapid increase in the use of industrial chemicals over the past 40 years," Blumberg said.
Although animal tests confirm the connections, it's still not clear exactly how the material interferes with cell functioning. The influence of bisphenol A on genetic functions in the fetus was compared by Saal with the accent over a French word.
"These little marks on the gene can totally change the way the gene functions. Until recently there were no methods to find these changes," he said.
Medical experts fear that soaring obesity rates are creating a global health crisis, causing diabetes, cancer, cardiovascular disease and hypertension.
Globally, more children are suffering from overweight than from starvation.
Obese people have problems breaking down normal dosages of pain medicine and antibiotics, according to George Corcoran and colleagues from Wayne State University in Detroit. The team found that the livers and kidneys of obese rats were twice as susceptible to toxic shock from medications and alcohol as were their cousins of average weight.
This tendency could also contribute to a higher death rate for the obese, he said.
By Gisela Ostwald, Dpa
© 2007 DPA
