The chemicals in our brains affect how we feel and what we do. As they fluctuate, we go from feeling good to bad to in-between. For a person with an eating disorder, a chemical imbalance can trigger feelings of chaos that lead to starving and binge-eating.
In the last decade, scientists have built a case for a biological and
genetic root of anorexia (the refusal to eat) and bulimia (the impulse to “binge and purge”, i.e., overeat and then vomit). Walter Kaye, the director of the Eating Disorder Research Program at the University of California, hopes to dispel the common perception that an eating disorder marks a person as vain, weak, or lacking in moral judgment.
“You talk to people who’ve had
anorexia and they say, ‘I just don’t know what happened. Suddenly this powerful force took over my mind and compelled me to act this way,’ ” Kaye says. For Kaye, eating disorders have more to do with brain chemistry than with the influence of popular media. But if we’re all exposed to the same images in the media, what drives some to eating disorders but leaves others unaffected?
In 1998, Kaye’s lab found that patients with bulimia have abnormally low levels of the brain chemical serotonin. Scientists have found that serotonin plays a key role in
emotions and mood disorders.
According to the serotonin theory of bulimia, when a person “binge-eats”, or consumes abnormally large amounts of food at random times, they feel a temporary high. The gorge of sugar and carbs causes serotonin to flood the bloodstream. It then binds with serotonin receptors in brain cells. As a result, the person feels the comfort their body craves. But with the overconsumption of food comes an overproduction of serotonin. This increase throws the person into anxiety, driving them to purge what they ate in attempt to regain control. When their serotonin level eventually lowers again, the desire to binge-eat returns.
Anorexics seem to have the opposite problem with serotonin. Doctors at London’s Maudsley Hospital found that anorexic patients had
abnormally high levels of serotonin in their brains. As anorexics skimp on calories, their serotonin level decreases and they feel a sense of calm. Because the body wants to prolong this feeling, it often drives a person with anorexia to starve themselves to maintain control.
The findings of Kaye and the
doctors at Maudsley suggest that, with effort, we can stabilize the powerful chemical imbalance that triggers eating disorders. But what causes these imbalances in the first place? Kaye and other researchers look to
genetics.
“If you don’t have a certain biology, you’re not going to develop an eating disorder,” said Kaye in a 2010 interview. According to Kaye, genetic variability accounts for 50 to 80 percent of predispositions to eating disorders. Kaye’s current research focusses on isolating which genes or gene variations make someone susceptible to anorexia or bulimia.
But genes don’t cause eating disorders on their own. In a 2012 conference, McGill professor Howard Steiger said, “If eating disorders are about anything, they’re about the ways in which environments switch on hereditary vulnerabilities.” Steiger and others believe that images in the media, intense peer pressure, and talking too much about weight can be triggers for those with inherited vulnerabilities. Steiger hopes that his work in genetics will contribute to the development of medication for eating disorders and promote the recognition of eating disorders as a mental illness rather than a lifestyle choice. “It’s not due to moral weakness or character flaws, but real susceptibilities, for which we can find real physical evidence,” says Kaye.
In the meantime, doctors continue to urge those who suffer from eating disorders to take the initiative to seek clinical therapy. As Ilona Burtan, a recovering anorexic patient, wrote in The Independent, “Anorexia isn’t a choice. Recovery is.”
