Eating disorders may have a stronger biological component than previously understood, with new research suggesting that genetic factors linked to binge eating and anorexia nervosa are distinct from those that influence body weight.
Researchers at Sweden’s Karolinska Institutet examined genetic information from thousands of people to investigate factors associated with eating disorder behaviours. Their findings suggest that these conditions cannot be explained solely by body image, weight or metabolism.
The study, published in Nature Mental Health, included nearly 40,000 people with binge-eating behaviour and about 25,000 people with anorexia nervosa. Researchers compared them with more than 1.2 million people without eating disorders.
The team identified genetic variations statistically associated with a greater likelihood of developing the conditions. Six genetic markers were linked to binge eating, while eight were associated with anorexia nervosa. Two of the markers connected to anorexia had not previously been identified.
Lu Yi, principal researcher at Karolinska Institutet’s Department of Medical Epidemiology and Biostatistics, said the findings showed that eating disorders were not simply related to body weight.
The researchers noted that many genetic variants associated with eating disorders differ from those that influence how much a person weighs. This points to a more complicated biological basis for the conditions.
Scientists can combine the effects of multiple genetic markers to produce what is known as a polygenic risk score. Such a score reflects the number and strength of genetic variants associated with a particular condition.
However, the researchers stressed that these genetic markers remain weak predictors when used on their own. Other biological, psychological and environmental factors would need to be considered when assessing an individual’s risk.
The study also identified links between genetic markers associated with eating disorders and other health and behavioural characteristics.
Some genetic markers connected to binge eating were also associated with traits involving impulse control, including smoking and risk-taking behaviour. They were also linked to higher body mass index and attention-deficit hyperactivity disorder.
Anorexia-related markers showed stronger genetic associations with obsessive-compulsive disorder.
The researchers said these differences suggest that binge eating and anorexia nervosa may involve partly separate biological mechanisms, even though both are classified as eating disorders.
Lisa Dinkler, an assistant professor at Karolinska Institutet, said the findings could eventually contribute to more targeted treatment approaches based on the specific characteristics of different eating disorders.
Eating disorders affect millions of people worldwide and are associated with serious risks to physical and mental health. They commonly involve disturbed eating patterns, intense concerns about food, weight or body shape, and significant effects on daily functioning.
Researchers said the findings could help shift the understanding of eating disorders away from a narrow focus on body weight and toward a broader view that considers distinct biological pathways.
