New UCSD study discovers differences in how the brain responds to food rewards in individuals with a history of bulimia nervosa. Image via health.ucsd.edu

A study of adults with bulimia nervosa showed that their brains respond to the taste of food whether they’re hungry or not, unlike others, researchers at the UC San Diego School of Medicine announced Monday.

The scientists said food is regulated by hunger and the hedonic reward of eating, and they wanted to determine which mechanism, or both, was disrupted in bulimia nervosa, which is characterized by binge eating, followed by purging to avoid weight gain.

Their findings, which could lead to new treatments, were published in the Journal of Abnormal Psychology.

“Our study suggests that adults with bulimia nervosa may have elevated reward-related brain activation in response to taste,” said Alice Ely, of the Department of Psychiatry at UCSD. “This altered neural response may explain why these individuals tend to remain driven to eat even when not hungry.”

The experiments involved 26 people with a history of the condition and 22 without. To measure brain activity, the group was administered water and a sucrose solution every 20 seconds for about 13 minutes following either a 16- hour fast or a standardized breakfast.

Ely, principal author of the report, said her team found that areas of the brain that determine how rewarding a taste might be and how emotionally important it is differed between the study groups. Such information is sent to parts of the brain that motivate eating.

The group without a history of BN responded to taste more when they were hungry than when they were satiated, but the group with a history of the disorder responded the same after eating as when hungry, she said.

Nearly 5 million females and 2 million males in America suffer from the condition. Treatment options, including cognitive and behavioral therapies, are effective for about 30 to 50 percent of patients.

“Our study results may contribute to identifying neural mechanisms that will open the door to the use of new medications or other brain-based behavioral treatments,” Ely said. “This is promising and hopeful news to those who suffer from eating disorders.”

Scientists at the University of Rochester Medical Center in New York and the Laureate Institute for Brain Research in Tulsa assisted with the study, which was funded, in part, by the National Institute of Mental Health.

— City News Service