Both alcoholism and eating disorders — such as anorexia and bulimia — are known to stem partially from inherited genetic factors.
In a 2013 Journal of Studies on Alcohol and Drugs study, researchers from the Washington University School of Medicine examined how these two diseases can intertwine on family trees.
“In clinical practice, it’s been observed that individuals with eating disorders also have high rates of alcohol abuse and dependence,” said Melissa A. Munn-Chernoff, PhD, the study’s first author. “Other studies have focused on the genetic connections between alcohol dependence and eating disorders, but all of those studies looked only at women. Ours was the first to include men as well.”
According to Munn-Chernoff, a postdoctoral research scholar in psychiatry, that’s important because although eating disorders tend to be thought of as a female problem, they affect men, too.
Genetics of alcoholism
Alcoholism is also known as alcohol dependence. People affected by this dependence have a longstanding pattern of alcohol intake that’s triggered changes in the chemical environment of their brains. In turn, these changes create a continuing need for alcohol to avoid symptoms of alcohol withdrawal. Prior to May 2013, the American Psychiatric Association (APA) officially designated alcoholism (alcohol dependence) as a separate mental health issue from alcohol abuse, a form of non-addicted alcohol use that creates many of the same life disruptions classically linked to dependence. However, the APA now uses the alcohol use disorder diagnosis to refer to all significantly dysfunctional forms of alcohol use.
Roughly half of any given person’s risks for alcoholism come from genetic factors, the National Institute on Alcoholism and Alcohol Abuse reports. However, there is no one gene that triggers alcohol dependence. Instead, multiple genes work together to increase an individual’s risks in one way or another. Specifically, a genetic influence may do such things as lower tolerance for alcohol’s intoxicating effects, increase the rate of alcohol-related chemical change inside the brain or make the body process alcohol in unusual ways. At the same time, some people have genetic configurations that lower their chances of developing alcoholism.
Types of eating disorders
The main eating disorders recognized by the American Psychiatric Association are anorexia nervosa, bulimia nervosa, binge-eating disorder and avoidant/restrictive food intake disorder (ARFID). All of these disorders feature established eating patterns that can produce serious, severe or fatal outcomes if not corrected through treatment. In a study published in 2011 in the journal Current Topics in Behavioral Neurosciences, a team of British researchers examined the genetic influences on disordered eating. These researchers concluded that genes involved with a range of body functions may raise the risks for any given individual. Examples of potential candidates include the genes that help regulate appetite levels, fat processing and storage, weight gain and the production of gender-specific hormones.
In the study published in the Journal of Studies on Alcohol and Drugs, the Washington University School of Medicine researchers used data gathered from almost 3,000 sets of twins to examine the hereditary connections between alcoholism and an eating disorder symptom called binge eating, which appears in varying degrees in people diagnosed with binge-eating disorder, bulimia and anorexia. Some of these twins were identical, which means they shared all of their genetic information. Other study participants were fraternal twins, which means they shared roughly 50% of their genetic information. The researchers used a comparison between the identical twins and the fraternal twins to detect the difference between the genetic and environmental influences on alcoholism and eating disorder risks.
After completing a complex set of statistical analyses, the researchers concluded that, in both men and women, roughly 26% of the genetic risk factors for alcoholism also play a role in the onset of binge eating. They also concluded that, in women, roughly 32% of the genetic risk factors for alcoholism play a role in the onset of the purging behaviors that people with bulimia (and some people with anorexia) use to eliminate the calories they take in during binge-eating episodes.
Study may help with treatment of both diseases
The authors of the study published in the Journal of Studies on Alcohol and Drugs caution that their research primarily involved people identified ethnically as Caucasian or white. This means that they don’t know for sure if the same genetic trends appear in people from other ethnic backgrounds. Even with these limitations, the study’s authors believe that their work will help doctors recognize the connection between alcoholism and eating disorders when treating their patients. Currently, doctors treating alcoholism don’t typically screen for the presence of eating disorders; conversely, doctors treating eating disorders often don’t screen for the presence of alcoholism.