07年VOA标准英语-Scientists Find Link Between Stress and Obesity

By Carol Pearson
Washington
16 July 2007
 

Midsection fat can lead to many health problems



Medical researchers have been looking for what some people call a "magic bullet" (magic pill) in their hunt to fight rising obesity rates worldwide.  In less than a decade, studies show, 75 percent of adults in the U.S. will be overweight.   Medical researchers have yet to find any "magic" cure for obesity, but scientists at Georgetown University in Washington say they have may have something close.  VOA's Carol Pearson explains.

Scientists have known for a long time about a link between chronic 2 stress and obesity. Now researchers at Georgetown University in Washington, D.C., recently made what they call a "stunning 3" advance.  

Dr. Zofia Zukowska, with Georgetown University's Medical School, says of the discovery, "The stunning thing is that we have actually discover(ed) the exact mechanism 4 by which people get fat when they are stressed and eat (a) high fat, high sugar diet. And by knowing the mechanism, we can now manipulate the fat."

Dr. Zukowska and colleague in lab



Dr. Zukowska and her colleagues put laboratory mice under the same type of stress they would experience in the wild such as meeting up with a more aggressive mouse.  They then fed these mice an equivalent of a fast food diet.  The mice became obese 5. 

Dr. Zukowska and her colleagues found an increased amount of a chemical called neuropeptide Y in these mice.  This chemical is activated 6 by stress and helps stimulate 7 the growth of fat cells. "So now you have a constellation 8 of more vessels 9 supplying nutrients 10 to the fat, fat cells multiplying and growing."

Obesity research on mice



And the fat in mice grew around their middle, just as it does in humans. Midsection fat is the most dangerous kind because it affects the heart and liver, causing heart disease, adding to cholesterol 11 levels, high blood pressure, diabetes 12 and stroke. But the researchers found they could block the fat-causing neuropeptide Y, or N.P.Y., for short, with a different chemical. 

"We found that in addition to reducing the abdominal 13 fat, we also improved the metabolism 14. And all those problems that the mice had such as hypertension and glucose 15 intolerance and fatty liver, it became markedly reduced or prevented" says Dr. Zukowska.

What is more, N.P.Y. seems to work in the human body much like it does in mice.  If so, Dr. Zofia Zukowska says it would be a major advance in the battle against obesity. "We think we not only are able to manipulate fat composition and maybe make the body more beautiful, but also actually treat obesity and metabolic 16 syndrome 17."

The researchers say many more studies need to be done before human trials can begin.