Mapping the genes behind eating disorders

Text: Anna Svensson, first published in Swedish in the magazine Medicinsk Vetenskap no 1/2021

There is a perception that eating disorders are caused by external circumstances, such as beauty ideals and social media. What does the research show?

“That’s a misconception. There’s no doubt that environmental factors matter, but we are all exposed to those environmental factors and far from everyone develops an eating disorder. Genetics helps us understand why certain people are more vulnerable to the pressure to be thin, maintain a negative energy balance, or lose weight. Blaming environment for everything, disadvantages individuals with these diseases as well as their family members, and it’s hindered the development of this field for decades. This isn’t about genes or the environment – it’s genes and the environment, and both must be taken into account when discussing both causes and cures.”

Now you’re launching a global study called the Eating Disorders Genetics Initiative (EDGI). Tell us more.

“Our previous studies, many of which were conducted in Sweden, have shown a strong genetic component for the development of anorexia nervosa. EDGI is a global attempt to collect hundreds of thousands of samples, in order to investigate genetic links to all types of eating disorders.”

“Participants fill out a series of questionnaires about their experiences with eating disorders, depression, anxiety, physical activity and other life events and factors. At the same time, their saliva is collected into a biobank. Once we’ve collected thousands of samples, we’ll extract DNA from the saliva and determine the gene set. We’ll then link the questionnaire answers to the genotypes, to answer questions about where on the human genome the genes that cause eating disorders are located, and how they can increase the risk of developing an eating disorder.”

What do you hope to achieve?

“Currently there are no medications that treat anorexia nervosa and very few for bulimia nervosa or binge eating. Our hope is to find ways to develop more medications or treatments.”

How will the study help people affected by eating disorders?

“Knowing that there is a genetic cause behind the disease reduces feelings of guilt and increases understanding about why recovery is so difficult. We don’t expect people with asthma or diabetes to learn how to breathe or produce their own insulin. Those who tell people with anorexia that they should ‘just eat’ or people with bulimia that they ‘shouldn’t eat so much’ don’t understand the strong biological mechanism that makes doing that just as hard as it is for asthmatics to ‘just breathe’. An individual with an eating disorder must of course actively choose to want to get better as part of the recovery process, but they need our support and understanding to be able to make the difficult decisions every day.”