New Differences Between Anorexic and Obese Brains Discovered
Researchers have discovered differences between the brains of anorexic and obese women. A study by the University of Colorado School of Medicine found that certain pleasure centres in the anorexic brain were overly sensitive while the same centres in the obese brain were desensitised.
"It is clear that in humans the brain's reward system helps to regulate food intake," study researcher Dr. Guido Frank, M.D., assistant professor director of the Developmental Brain Research Program at the University of Colorado School of Medicine, said. But "the specific role of these networks in eating disorders such as anorexia nervosa and, conversely, obesity, remains unclear."
In the study, the women’s brain reward circuits were triggered using sweet and nonsweet-tasting liquids. The resulting brain activity was measured via an fMRI scan. The women with anorexia had a high level of brain activity, suggesting they get a greater brain reward from eating. Obese women had a much lower amount of brain activity. This could mean that obese people may have to eat more to get the same brain reward as an average person while anorexics may get a brain reward before they have eaten enough.
This idea is backed up by research in mice from 2008 which showed an association between problems signalling for dopamine in the brain and obesity. "Baseline dopamine levels were 50 percent lower and stimulated dopamine release was significantly attenuated in the brain reward systems of obesity-prone rats, compared with obesity-resistant rats," study researcher Emmanuel Pothos, Ph.D., an assistant professor in pharmacology at Tufts University School of Medicine, said.
Previous studies have also connected dopamine with eating.
As people eat, the brain releases dopamine to, in a sense, reward a healthy behaviour. If someone is not getting enough food, the body produces larger amounts of dopamine. This means obese people may be over eating in an attempt to get the same satisfied feeling an average person receives from a normal meal.
While it is still too early to draw any conclusions from the research, the data may help answer many questions about eating disorders. It could even be instrumental in the eventual creation of an eating disorder treatment.