- The Washington Times - Thursday, March 20, 2003

BOSTON
Binge eaters who say they can't help it may be right. A study suggests a weak gene, not feeble willpower, may be the cause in some cases. The research may point the way to a future pill to tame the appetites of binge eaters.
The joint Swiss-German-American study makes the strongest case yet that genetic mistakes can cause eating disorders, researchers say. Eating behavior traditionally has been viewed as complex and cultural.
"Willpower is not always important to reduce weight. Some people can by willpower. Some cannot, and I think these patients have a hard time," said Dr. Fritz Horber, leader of the binge-eating study at the Hirslanden Clinic in Zurich.
Researchers have been trying to understand the reasons for an epidemic of obesity, which raises the risk for heart disease, diabetes and many other ailments. About 30 percent of American adults are obese, up from 14 percent 25 years ago, government data show. The surge is blamed widely on abundant high-calorie foods and sedentary lifestyles.
However, some researchers have begun to link several genes to obesity, implicating heredity as an important underlying factor. Eating problems increasingly are thought to stem from a subtle interaction of lifestyle and multiple genes.
Binge eating, likely the most common eating disorder, strikes up to 4 million Americans, the National Institutes of Health says. Binge eaters, who are usually but not always overweight, frequently and compulsively stuff themselves often in secret and feel ashamed afterward.
In the Hirslanden Clinic study, which was published today in the New England Journal of Medicine, the researchers focused on a gene linked to obesity in earlier studies. Known as the melanocortin 4 receptor gene, it makes a protein by that name that helps stimulate appetite in the brain's hunger-regulating hypothalamus. If a mutated gene makes too little protein, the body feels too much hunger.
The researchers considered 469 severely obese white adults a quarter of them binge eaters. However, the disorder was much more common among the 5 percent with the mutated gene. All of them were binge eaters, compared with 14 percent of those with no mutated gene.
In another study in the same journal issue, a British team reported finding mutations of the same gene in more than 5 percent of 500 severely obese children. The genetic link was so strong that the researchers could use results from chemical tests on their genetic DNA to predict how much the children would eat at a meal.
Dr. Horber, the Swiss researcher, said other eating disorders, including other types of bingeing, probably stem from a variety of genes and environmental factors. However, he said the still-unnamed binge-eating syndrome tied to this gene is especially important because it is perhaps the most stubbornly resistant to dieting and exercise.
Dr. Horber said the binge eaters in his study felt a wave of relief from guilt when they learned of the genetic cause behind their compulsion. Dr. Stephen O'Rahilly, one of the British study's researchers at the University of Cambridge, said one family in that study was so ecstatic over evidence of a physical cause that they made themselves T-shirts saying, "We've got an MC4 mutation."
Eric Ravussin, a Louisiana State University researcher on obesity genetics, said, however, that without more biochemical proof, he remains "a little bit skeptical" that these mutations and not others located nearby on the same chromosome are the syndrome's precise cause.

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