Science Takes On Supersize

Science Takes On Supersize

By Jocelyn Selim|Friday, September 09, 2005

Touching off a megaflap, Centers for Disease Control scientists reported in April that mildly overweight people had a lower risk of premature death than those of normal size. Since then, the CDC has taken a step back—adjusting obesity mortality statistics, among other things. Meanwhile, new fat studies abound:

Fat accelerates aging
After examining 1,122 adult women, molecular biologist Tim Spector of St. Thomas’ Hospital in London concluded that extra pounds can age white blood cells as much as 8.8 years. It is unclear how the entire body is affected because Spector looked only at telomeres, nucleotides on the ends of chromosomes that slowly erode as cells copy themselves during normal aging. But years of animal studies suggest a strong link. Smoking also ages cells, Spector found. Women who smoked a pack a day for 40 years added as much as 7.4 years to their blood cells’ age.

Fat vaccine tested
You can get shots for polio, measles, and the mumps—why not for obesity? Ordinary vaccines work by provoking an immune response to detoxified viruses or bacteria. So a fat vaccine, Swiss scientists reason, should work by provoking an immune response to ghrelin, a hormone that normally tells us to eat. Mice given an experimental vaccine developed by Cytos Biotechnology in Zurich, Switzerland, remained an impressive 15 percent lighter on an all-you-can-eat high-fat diet. Exactly how ghrelin triggers eating is still a mystery, and scientists aren’t sure that derailing the hormone won’t produce unwanted side effects. More information should be forthcoming after results of the company’s tests on 112 human volunteers this summer become public.

Fat burns fat
Endocrinologist Clay Semenkovich of Washington University in Saint Louis has intriguing news for low-fat dieters: To burn fat, you have to eat more of it. Semenkovich genetically engineered mice so that they no longer had the ability to make new fat themselves. He then fed them a fat-free diet. Instead of slimming down, the mice developed low blood sugar, diabetic tendencies, and fatty livers worthy of pâté. But when the mice resumed a diet that included fat, their metabolisms returned to normal. “Without new fat, the mice could successfully mobilize stores of body fat to the liver but couldn’t process it once it was there,” says Semenkovich. He is now working to identify the specific type of fat the body needs to burn off the pounds. And one day, he says, whatever it is could be sold in pill form.

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