The question of what causes eating disorders has puzzled the medical community since “wasting disease” was first described in the 17th century.

Today, researchers and clinicians agree that, in addition to psychosocial and environmental risk factors, there is a strong biological basis to these disorders.

Now, new data from a Massachusetts General Hospital researcher suggests that exposure to common childhood infections, such as strep throat or bronchitis, may significantly raise a person’s risk of developing anorexia nervosa, bulimia nervosa and other eating disorders.

Results of the population-based study, published in JAMA Psychiatry, found that infections that required hospitalization or treatment with anti-infective medications, such as antibiotics, antifungals or antivirals, increased the risk of developing an eating disorder by as much as 39%.

The multi-institutional study, which analyzed the health histories of more than 500,000 adolescent girls in Denmark, also found that recurrent infections and repeated treatment increased the risk.

Infections and Behavior

“Infections and inflammation more broadly have been recognized to play a role in psychiatric diseases like schizophrenia, but this has been less explored in eating disorders,” says Lauren Breithaupt, PhD, a clinical psychologist in the Mass General Eating Disorder Clinical and Research Program, and lead author of the study.

“We’re hoping that a better understanding of the relationship between the immune system and disordered eating will help identify a mechanism behind the increased risk and biochemical changes we see happening.”

As an observational study, the findings don’t point to a single cause or effect, but one possible explanation, according to Dr. Breithaupt, is that the infection or treatment of the infection disrupts the gut microbiome, which in turn alters the brain’s neurobiological reward system.

Another possibility is the body’s own inflammatory response. Inflammatory proteins have been shown to cause changes in behavior, such as loss of appetite.

“Infections, by and large, have typical behaviors associated with them, and among those most commonly reported is loss of appetite,” Dr. Breithaupt says. “If you’re already at risk for an eating disorder, this period of no appetite could have a priming effect.”

Although more research is needed, Dr. Breithaupt is encouraged the findings further enforce the biological nature of the disease.

Eating Disorder Stereotype

“Eating disorders have long been seen as social constructs — think of the stereotype of the wealthy white girl who isn’t eating because she wants to look a certain way,” says Dr. Breithaupt.

“It’s taken a lot of evidence — more than most other mental illnesses — to blow that stereotype out of the water. We now know that the rates are similar across the world and across cultures. We’re even seeing that there may not be as big a gender discrepancy as we previously thought.”

Despite mounting biological evidence, there is still a great deal of confusion in the medical community about how to diagnose and treat eating disorders.

Dr. Breithaupt is hopeful that the team’s findings can lead to increased awareness of the signs and symptoms and that more hospitals and treatment centers adopt a more scientific approach to treating these diseases.

The Role of Philanthropy

“The Eating Disorders Clinical and Research Program at Mass General offers gold standard evidence-based treatment for eating disorders, but we receive so many referrals per year that unfortunately we can’t treat every patient who seeks services,” she says.

“That’s why philanthropy is so important to the growth of our program. The work that we do is often funded by individuals and families who have been touched by these diseases.”

The other key to advancing the understanding and treatment of eating disorders, Dr. Breithaupt says, is education. “In order to identify biological markers, we need larger sample sizes and data sets, which requires individuals with the disorder to come forward and to participate in research,” she says.

“By educating the public about the biology underlying eating disorders, we can break down barriers and overcome the stigma.”

This article was first published on the Mass General Giving site

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