Women suffering from anorexia have "distinct" differences in the part of the brain that recognizes taste, according to new research reported online by the journal, Neuropsychopharmacology, in advance of publication.
Although anorexia nervosa is categorized as an eating disorder, it is not know whether people suffering from the disease have alterations in the regions of the brain that regulate appetite. But researchers say they've now learned that people with the disorder have differences in the portions of their brains that regulate taste and judge how rewarding that taste is to the person.
In a recent study led by Dr. Angela Wagner, of the University of Pittsburgh School of Medicine, and Dr. Walter H. Kaye, of the University of Pittsburgh and the University of California, San Diego (UCSD) schools of Medicine, the brain activity of 32 women was measured using functional magnetic resonance imaging.
The research team looked at images of the brains of 16 women who had recovered from anorexia nervosa — some of whom had been treated at the Center for Overcoming Problem Eating at Western Psychiatric Institute and Clinic of the University of Pittsburgh Medical Center — and 16 control subjects.
They measured the women's reactions to pleasant taste (sucrose) and neutral taste (distilled water.)
Imaging results showed that women who had recovered from anorexia had significantly reduced response in the insula and related brain regions when compared to the control group. And, while the controls showed a strong relationship between how they judged the pleasantness of the taste and the activity of the insula, this relationship was not seen in those who had recovered from anorexia.
According to Kaye, it is possible that individuals with anorexia have difficulty recognizing taste, or responding to the pleasure associated with food.
“We know that the insula and the connected regions are thought to play an important role in interoceptive information, which determines how the individual senses the physiological condition of the entire body,” said Kaye, in a news release. “Interoception has long been thought to be critical for self-awareness because it provides the link between thinking and mood, and the current body state.”
Because this region of the brain also contributes to emotional regulation, it may be that food is aversive, rather than rewarding to anorexics, the researchers wrote. This could shed light on why individuals with anorexia avoid normally “pleasurable” foods, fail to appropriately respond to hunger and are able to lose so much weight, they said.