Gut Bacteria May Affect Appetite, Study Finds

Rebecca Lewis February 11, 2015

Researchers have found possible link between specific bacteria present in the human gut flora and the eating disorders like anorexia nervosa, bulimia, and binge eating. The new study suggests that correcting the imbalances in the gut flora and normalising satiety signals could potentially help restore a healthy food intake.

For the study, scientists altered the intestinal flora of mice to see the impact of different types of E. coli on their immune system and behaviour.

When the animals were given E. coli that produced ClpB, disordered eating behaviour was observed. Eating behaviour was normal in mice given mutated E. coli bacteria that did not produce ClpB. Tests on 60 eating disorder patients showed greater antibodies to ClpB and alpha-melanotropin compared with the general population, suggesting raised levels of ClpB.

A molecular mechanism linked to risk for anorexia nervosa, bulimia, and binge eating disorder has never been established. This study confirms the involvement of ClpB in appetite regulation, suggesting that “specific alterations of gut microbiota may lead to behavioural and emotional abnormalities as observed in eating disorder patients.”

“Our findings of increased levels of anti-ClpB antibodies in eating disorder patients, and correlations of anti-ClpB antibodies with patients’ psychopathological traits, support the involvement of ClpB-expressing microorganisms in abnormal feeding behaviour,” according to the researchers from the Inserm Laboratory on Nutrition, Gut and Brain in Rouen, France.

This “opens up new perspectives for the diagnosis and specific treatment of eating disorders,” says the team. “According to our initial observations, it would indeed be possible to neutralize this bacterial protein using specific antibodies, without affecting the satiety hormone.”

In addition to pharmaceutical drugs, the human gut microbiome can also be altered via diet. This phenomenon has been explored by Peter J. Turnbaugh, Ph.D., assistant professor of microbiology & immunology at Harvard University, Cambridge, Mass. “Dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut.” He adds that even short-term consumption of diets composed entirely of animal or plant products “alters microbial community structure.” he explained.

The new findings suggest that animal-based diets increase microorganisms including Alistipes, Bilophila and Bacteroides, and reduce the levels of bacteria that metabolize plant components. The changes reflect “trade-offs between carbohydrate and protein fermentation,” he says. His findings also support a link between dietary fat and “the outgrowth of microorganisms capable of triggering inflammatory bowel disease.”

The findings were published in the journal Translational Psychiatry.

Source of this article: Gut Bacteria May Affect Appetite