Researchers have gained new insight into an eating disorder called ARFID, and the work has revealed that genetics are having a strong influence on the condition. The National Eating Disorders Association defines eating disorders as mental and physical illnesses that can affect people of any age, gender, culture, race, weight, or body shape. These disorders are thought to have complex causes that may involve psychological, biological, or sociocultural factors. Avoidant restrictive food intake disorder (ARFID) is an updated DSM-5 term for an eating disorder that was previously called “Selective Eating Disorder.” About one to five percent of people are estimated to have ARFID.
Unlike anorexia, ARFID is not related to fears of fatness or distress about body shape; ARFID is a lack of interest in food or eating that can cause serious weight loss and nutritional deficiencies, and may lead to a loss of physical function or psychological problems. It is not related to a lack of food or any cultural practice, and is not attributable to another medical disorder. However, when it occurs along with other diseases, the eating disturbance is significantly worse than a typical side effect of that condition would be on its own. ARFID patients tend to avoid food because of discomfort they experience that relates to food's characteristics; people may fear choking or food poisoning, dislike the way food looks, or simply lack an appetite.
Twin studies can reveal more about how strongly genetics factor into some characteristic. For example, if both twins carry some trait, that trait is very likely to have a significant genetic component, while if a trait is only observed in one identical twin and not the other, the trait is less likely to be due to genetics.
When scientists assessed almost 17,000 pairs of Swedish twins born from 1992 to 2010, they found 682 kids with ARFID between the ages of six and twelve. Genetic factors seem to have a significant effect on the incidence of ARFID; the work showed that 79 percent of ARFID risk is related to genetic components. The findings have been reported in JAMA Psychiatry.
“This study suggests that ARFID is highly heritable. The genetic component is higher than that of other eating disorders and on par with that of neuropsychiatric disorders such as autism and ADHD,” said study co-author Lisa Dinkler, a postdoctoral researcher at the Department of Medical Epidemiology and Biostatistics at the Karolinska Institutet.
Now, Dinkler and colleagues want to learn more about the environmental and genetic links between ARFID and other diagnoses including anxiety, depression, neurodevelopmental disorders, and gastrointestinal problems.
Sources: Karolinska Institute, JAMA Psychiatry