MRIs Detect Chemical Signs of Anorexia

 

Stefany Chen/Guardian

After conducting imaging studies of the brain, scientists at the UCSD School of Medicine have discovered a neurological cause of anorexia that could lead to more effective treatment in the future.

The experiment began when scientists noticed that anorexia and bulimia tended to be passed down through family members. This indicated a genetic cause behind eating disorders and motivated Dr. Walter Kaye and his research team to begin searching the brain for an explanation.

They began their tests in the area of the brain called the insula which regulates interoceptive awareness, or the way your body responds to internal changes like a lack of food or oxygen.

Using functional magnetic resonance imagine (MRI), Scientists began testing the neurological reactions recovering anorexia patients to the taste of sugar. This machine enabled them to view changes in blood flow in the brain that occur as a result of neural activity.

In someone without an eating disorder, the insula releases hormones for pleasure when presented with the taste of sugar, especially after a long period of hunger.

However, anorexic individuals did not react as strongly to the taste of sugar, indicating a problem in the part of the brain that conveys rewards or emotions.

“So if you feel pain, or you hold your breath, then there’s dramatic change of internal body states,” Kaye said. “[The insula] lights up and gives you a message saying ‘Yeah, okay, something’s changed, something’s wrong.’ [Anorexic patients] have an altered sense of self-awareness.”

By decreasing the amount of positive feedback the body gets from food and genetically enabling an individual to resist food for long periods of time, scientists concluded that a deficiency in this area of the brain can predispose someone toward anorexia.

This deficiency in the function of the insula occurs as a result of an imbalance in the levels serotonin and dopamine.

Dopamine is the hormone that gives a sensation of pleasure when your brain is exposed to food, sex, or drugs. Serotonin effects aggression and anxiety levels, especially in social situations.

According to Kaye, not only do those with anorexia not receive the heightened sensations of pleasure when exposed to food, but anorexics also experience an increase in serotonin levels — as frequently happens when one consumes carbohydrates — which can actually lead to increased anxiety when someone eats.

Researchers also found that these problems in introspective awareness manifest at a young age. Adults or teenagers with anorexia often exhibit childhood signs of anxiety, perfectionism, obsessive compulsive disorder or difficulty changing mindsets.

Researchers are hoping to transform these findings into new treatments for anorexia and bulimia patients, or develop an early warning system.

Kaye predicts the project will continue for another five years.

“We’re working on finding the gene responsible for these, but we have a long way to go,” Kaye said.

Anorexia is currently the psychological disorder with the highest mortality rate, and those suffering from it are more likely to encounter other mental disorders like severe depression and OCD. Today, and treatment methods rely heavily on various forms of psychotherapy, such as family therapy.

The UCSD Eating Disorders Program will sponsor Eating Disorders Awareness Week, which takes place the last week in February and kicks off with a walk at Mission Bay at 10 a.m. on Feb. 21.

Readers can contact Hayley Bisceglia-Martin at [email protected].

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