The brain's response to taste stimuli is associated with high anxiety and an urge for dilution that could play a role in anorexia nervosa, researchers from the University of Colorado's Anuschutz Medical Campus found
The researchers around Dr. Guido Frank, MD, associate professor of psychiatry and neuroscience at the University of Colorado School of Medicine, analyzes a group of 52 patients with anorexia nervosa tasting sugar during
They found that their brain response was higher than that in the control group of 52 healthy subjects, representing a Biolo clinical marker for the disease. At the same time, this brain response was associated with high anxiety and low weight gain for those treated for anorexia nervosa.
dopamine reward cycle
Dr. Frank found that while these patients restricted their diet, a brain reward cycle associated with the neurotransmitter dopamine becomes more active, but also triggers anxiety. This makes food avoidance worse and perpetuates the often deadly disease.
"As you lose weight, your brain reward reaction increases, but instead of eating, we believe that it increases the anorexia nervosa, which makes it more restrictive, which then becomes a vicious circle"
The study included 56 female adolescents and young adults with anorexia nervosa between the ages of 1
Those with the eating disorder responded more strongly to the unexpected receipt or not receipt of sugar water, perhaps because of the release of dopamine
Higher Harm Avoidance
The researchers found that the higher the brain response, the higher the damage prevention in anorexia nervosa. Avoidance is a fearful measure of excessive worry and anxiety. In these patients, it drives the urge for slimness and promotes body dissatisfaction.
The higher the brain response, the lower the weight gain during treatment.
This brain reward reaction acted on the hypothalamus, which stimulates the food, in the anorexia nervosa group. The researchers hypothesized that this might allow signals to be overdriven and fended off.
"An enhanced response of the dopamine reward system is an adaptation to hunger," the authors write. "Individuals susceptible to developing anorexia nervosa may be particularly sensitive to food restrictions and adaptations of the reward response during development [mid-adolescence]."
According to Frank, the behavior of anorexia nervosa could alter the circuits of the brain and affect its taste-reward processing mechanisms. Those who are already concerned about shape and weight are getting even more worried.
And a strong reaction that says "feeds me" could be overwhelming and trigger more food restriction than food.
The study found that most people like sweet-tasting things, those with eating disorders associate the taste with weight gain and try to avoid it. Frank found that brain activation in the anorexia group was conversely associated with every pleasant experience of eating sugar.
"Our data show that adolescents with anorexia nervosa were negatively conditioned to the sweet taste in this study and may have developed an inverse association with dopamine release via the larger (brain) reward circuit"
Frank believes that these insights could lead to new treatments for eating disorders.
The work was supported by grants from the National Institute of Mental Health, the National Institutes of Health, the University of Colorado's Neuroscience program from the National Institutes of Health, and the National Center for Advancing Translational Sciences at Colorado's Clinical and Translational Science Awards.
Frank GKW, DeGuzman MC, Shott ME, Laudenslager ML, Rossi B, Pryor T
Association of Brain Reward Learning Reaction with Damage Prevention, Weight Ga in, and Hypothalamic Effective Connectivity in Adolescent Anorexia Nervosa
JAMA Psychiatry. Published online on July 19, 2018. doi: 10.1001 / jamapsychiatry.2018.2151
Image: Laura Lewis / Flickr