Anorexia and bulimia fix? Biological link to appetite found

Eating disorders could soon join the growing number of mental illnesses that have a biological link.

New research shows that a protein produced by some intestinal bacteria could be the source of disordered eating, from anorexia to bulimia.

Eating disorders are estimated to affect about 15-20 percent of the general population, and evidence is growing to show that eating disorders could also be triggered by biological issues related to appetite.

“Ten years ago, we discovered the existence of some antibodies attacking melanotropin, the hormone produced by the brain that controls satiety, and we did measure a high concentration of these antibodies in the system of people suffering from eating disorders,” co-author Dr. Serguei Fetissov tells Metro.

The goal of the University of Roeun study was to find out where these antibodies originated. Focusing on the bacteria E. Coli, which occurs naturally in the human gut, Fetissov’s team observed that when under stress, this organism could create a protein, ClpB, that mimics melanotropin and stimulates the production of antibodies attacking both the protein and melanotropin. This disrupts appetite, increasing the cravings of binge eaters and decreasing them in anorexics.

“Anorexia and bulimia are caused by combined effects of biological and environmental causes,” said Fetissov.The social pressure surrounding weight creates enormous stress, particularly on young women, to start diets:“The restrictions involved have a direct influence on the biology of the intestine because the bacteria are put under a situation of stress, and therefore produce this protein that deregulates their appetite.

“The social factors would trigger the eating disorders, but the protein would be responsible for its persistence – it’s a viscious cycle,” he adds.

Now that the protein has been identified, does it mean that some kind of drug to neutralize it could be the long-awaited answer to eating disorders?

“An antibiotic would kill any bacteria without being able to target one kind, so the idea would be to find a selective antibiotic, which doesn’t really exist today, to reduce the production of the protein,” he said.

The team’s next step is to develop a blood test based to detect ClpB. “If we are successful in this, we will be able to establish specific and individualised treatments for eating disorders,” Fetissov said.