Healthcare (Commonwealth Union) – Genes have been a key focus in relation to disease, however the extent to which they play a role in particular diseases has been debated.
An international research project involving the University of Otago and hundreds of New Zealand participants has identified unique genetic patterns associated with binge eating and anorexia nervosa, challenging the long-held assumption that eating disorders are primarily caused by psychological factors.
The study, led by scientists at King’s College London and the University of North Carolina, is the first large-scale effort to identify and compare the genetic profiles of binge eating and anorexia nervosa side-by-side.
The research, published in the journal Nature Mental Health, includes DNA data from more than 500 New Zealand participants provided by a University of Otago Faculty of Medicine – Christchurch Ōtautahi research team.
What do the results tell us? There appear to be some genetic similarities between binge eating and anorexia nervosa, particularly with psychiatric disorders. However, each disorder also has its own biological traits that distinguish it from the other.
Associate Professor Jenny Jordan, a clinical psychologist in the Department of Psychological Health, stated the research challenged the long-held belief that eating disorders could be explained only by psychological factors.
She indicated that they know both conditions are classified as eating disorders, but at a fundamental level they seem to have important biological differences.
The study offers some of the strongest evidence to date that eating disorders are influenced by a combination of psychiatric and metabolic factors according to Professor Martin Kennedy, Department of Pathology and Molecular Medicine.
By looking at DNA samples of tens of thousands of people worldwide with binge eating or anorexia nervosa, he said they are beginning to find genetic patterns unique to each disorder.
Scientists have for the first time identified six regions of the genome associated with binge-eating behaviour, including a region near FTO, a gene already known for its role in regulating body weight.
The study also identified eight regions of the genome linked to anorexia nervosa. Eating disorders are genetically linked to a number of psychiatric disorders including depression and anxiety, researchers found. However, the nature of these associations differed, with anorexia nervosa being more genetically overlapping with obsessive-compulsive disorder and binge eating more closely associated with attention-deficit/hyperactivity disorder (ADHD).
Genetic traits that predisposed to greater body weight were also linked with a higher propensity to binge-eating behaviours. By contrast, anorexia nervosa showed the opposite pattern: genetic factors associated with higher body weight appeared to have a protective effect against developing the condition.
Importantly, the results suggest that the genetic roots of eating disorders cannot be explained by genes that affect body weight or body mass index (BMI) alone.
The results support the theory that eating disorders are “metabo-psychiatric” disorders — disorders resulting from a mix of metabolic processes and psychiatric genetic factors.
For Associate Professor Jordan, the findings represent a seismic shift in how researchers view and approach the treatment of eating disorders.
These results add to our comprehension of the common and distinct biological drivers of these eating-related traits, she said. They may also aid in developing more targeted treatments based on the specific biology of each disorder.
Eating disorders can affect individuals of all body sizes and may lead to severe physical and mental health impacts. Acknowledging the complex biological factors involved could help pave the way for treatments that are more personalised and better aligned with the underlying mechanisms of each condition.
Professor Kennedy says the involvement of New Zealand researchers is also strengthening the foundation for future studies in the field.
He indicated that this research is helping to uncover the genetic and biological mechanisms that contribute to eating disorders, opening the door to more effective treatments and, ultimately, better prevention strategies.
“We are excited that so many New Zealand participants have agreed to contribute to these important international studies.”
