Genetic Factors Behind Eating Disorders

Are eating disorders genetic? Researchers think so—eating disorders can be a result of both genetic and environmental influences.

Several studies suggest that people with anorexia share genetic abnormalities. While similar studies haven’t been conducted on bulimia nervosa and binge eating disorder, researchers still believe these eating disorders have a genetic component.

Researchers say that between 40% and 60% of the vulnerability to eating disorders comes from genetic factors. [1] Understanding what those genes are could lead to better treatment options. But conducting all of the necessary research will take time.

In the interim, know that eating disorders can be successfully treated. If you’re struggling with unhealthy eating, talk with your doctor about treatment programs that could help.

Anorexia Nervosa and Genetics

Genetic studies suggest that people with anorexia share a set of genetic abnormalities. Of all the eating disorders, anorexia has been studied most by geneticists. The lessons these researchers have learned could help us understand other eating disorders better.

Researchers say anorexia runs in families. People born into a family touched by anorexia are 11 times more likely to develop the condition when compared to others. [2]

People with anorexia may have abnormalities in genetic factors that regulate the following:

• Cholesterol production
• Body mass index and obesity
• Fasting insulin
• Fasting glucose

As a result, researchers say they consider anorexia a disease with roots in mental health and metabolism. [2]

The genetic roots of anorexia were first discovered in groundbreaking research published in 2003. Here, researchers found three candidate genes involving appetite, anxiety, and depression that were all unusual in people with anorexia. [3] Researchers have built on this study over time, deepening our understanding of how this eating disorder works.

Can Other Eating Disorders Be Genetic?

Genetic studies involving people with bulimia and binge eating disorders are relatively rare. [4] While it’s clear that many people struggle with these forms of disordered eating, researchers just haven’t dug deep into the genetic roots yet. That may change in the future.

In a small study, researchers found a shared genetic risk factor in people with binge eating disorder. [5] A study like this suggests that genetic factors contribute to the development of this eating disorder. Still, more work must be done to make the relationship clear and easy to understand.

How Genetics Influence Eating Disorders

Some researchers argue that we don’t need to conduct new studies on people with binge eating disorder and bulimia. Instead, they say we can think of all eating disorders as interrelated.

In this model, people with all eating disorders share the same genetic vulnerabilities. But how those genes are expressed accounts for the differences in behavior.

For example, researchers say that mutations in the same gene could cause people to do the following: [6]

• Restrict: Someone with this variant would develop anorexia and limit food intake.
• Indulge: Someone with this variant would binge and develop bulimia or a binge eating disorder.

Genes also don’t work independently, and it’s common for a person’s cells to interact and overlap. As a result, some genetic information is expressed, and other information is suppressed. Researchers say this action could be responsible for the different presentations of eating disorders.

Some people have a genetic predisposition to put on weight, and others are genetically inclined to stay slim. If these genes interact with those involving eating disorders, they could influence whether someone binges or restricts food. [7]

Genes Connected to Personality Traits

Some genes that contribute to eating disorders are associated with specific personality traits. They are believed to be highly heritable and often exist before the onset of the eating disorder. These traits are:

• Obsessive thinking
• Perfectionistic tendencies
• Sensitivity to reward and punishment
• Emotional instability
• Hypersensitivity
• Impulsivity
• Rigidity

Family studies of anorexia and bulimia have found a higher lifetime prevalence of eating disorders among relatives of eating disorders. [8]

Twin studies also suggest that genetic factors significantly influence both anorexia and bulimia. When looking at the differences between identical and fraternal twins, correlations are two times greater in identical twins with eating disorders.

The Future of Genetic Research

Studies involving eating disorders may seem simply academic. But how important is it to understand the genes underpinning eating disorders? Researchers say their work could have real-time benefits but need more time.

Researchers identified eight specific genetic loci linked to eating disorders in one study. They suggest there are hundreds more. [9] It will take time to tease out connections and determine how genes are expressed in different people.

But when the research is complete, doctors may have more treatment options to help their patients. Molecules targeting specific genetic pathways could help curb harmful eating impulses. [10]

Drugs like this could help people develop healthier eating patterns quickly. But those drugs will take years to develop and test.

Eating Disorders as a Biological Illness

Genetic findings can help researchers, medical providers, therapists, and treatment teams to see eating disorders as biological illnesses where individuals share temperament predispositions. Still, researchers say 30% to 50% of eating disorder risk is due to environmental factors.

Study 1: Anorexia Nervosa Changing Genes

A Canadian study on anorexia found that those who struggle with anorexia over a long period develop changes in how genes are expressed, otherwise known as epigenetics. It works by a process called methylation, where the level of methylation of a gene determines whether the gene is turned off. [11]

A researcher in the study states that eating disorders tend to become more entrenched over time. These findings point to physical mechanisms acting on physiological and nervous system functions throughout the body.

Study 2: Eating Disorders and Alcohol Dependence

In a further study by the Washington University School of Medicine in St. Louis, researchers found that eating disorders and alcohol dependence may share some of the same genes. [12] Data gathered from 6,000 adult twins in Australia suggests that common genetic factors underlie alcoholism and specific eating disorder symptoms, such as binge eating and purging habits that include self-induced vomiting and the abuse of laxatives.

These findings show that identical twins share 100% of their genetic makeup, while fraternal twins share about half. When comparing identical to fraternal, researchers can develop estimates of how much is due to genes versus environmental factors.

Ultimately, genetic factors behind eating disorders are complex and need further study and advancement. Genetic factors can play a role in the development and onset of eating disorders but do not fully define the causality of an eating disorder.

What Else Causes Eating Disorders?

People are more than a collection of genetic materials. We’re all shaped by our families, cultures, and relationships. So while genes could influence your risk of developing an eating disorder, many other risk factors exist.

Common risk factors for eating disorders include: [13]

• Psychiatric disorders: Inflexibility, perfectionism, and body image dissatisfaction could influence the development of an eating disorder. In addition, other mental health issues, such as obsessive compulsive disorder (OCD), can put you at a greater risk of developing eating disorders.
• Social environment: Weight-based teasing, cultural influences, limited social networks, and historical trauma are all part of eating disorder development.
• Biological: A history of dieting and some medical issues (including diabetes) could raise your risk.

When treating eating disorders, any co-occurring issues must be considered and treated simultaneously, especially any major psychiatric disorders or physical symptoms that may be present.

No matter what causes your eating disorder, you can get better. Current treatments may not be based on genetics, but they have helped thousands of people overcome harmful eating patterns and eating disorders and develop healthier lives.

If you’re struggling with your eating or are concerned about someone else, get help today.

References

1. Bulik C. (2021). A Better Understanding of Eating Disorders and Genetics. UNC Health. Accessed September 2022.
2. Bulik CM, Blake L, Austin Jehannine. (2019). Genetics of Eating Disorders. Psychiatric Clinics; 42(1):59-73.
3. Beckman M. (2003). How Eating Disorders Are Inherited. Science. Accessed September 2022.
4. Himmerich H, Bently J, Kan C, Treasure J. (2019). Genetic Risk Factors for Eating Disorders: An Update and Insights into Pathophysiology. Therapeutic Advances in Psychopharmacology; 9.
5. Genetic Risk Factor for Binge Eating Discovered. (2016). Boston University School of Medicine. Accessed September 2022.
6. Mayhew AJ, Pigeyre M, Couturier J, Meyre D. (2018). An Evolutionary Genetic Perspective of Eating Disorders. Neuroendocrinology; 106:292-306.
7. Deciphering the Genetics Behind Eating Disorders. (2021). Science Daily. Accessed September 2022.
8. Berrettini W. (2004). The Genetics of Eating Disorders. Psychiatry; 1(3):18-25.
9. Lewis T. (2019). Anorexia May Be Linked to Metabolism, a Genetic Analysis Suggests. Scientific American. Accessed September 2022.
10. Paolacci S, Kiani AK, Manara E, Beccari T, Ceccarini MR, Stuppia L, Chiurazzi P, Ragione LD, Bertelli M. (2020). Genetic Contributions to the Etiology of Anorexia Nervosa: New Perspectives in Molecular Diagnosis and Treatment. Molecular Genetics and Genomic Medicine; 8(7):e1244.
11. Warmflash D. (2015). You Are What You Don’t Eat: Genetics of Anorexia and Bulimia. Genetic Literacy Project. Accessed September 2022.
12. Dryden. (2013). Alcohol Abuse, Eating Disorders Share Genetic Link. Washington University in St. Louis. Accessed September 2022.
13. Risk Factors. (n.d.). National Eating Disorders Association. Accessed September 2022.

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The opinions and views of our guest contributors are shared to provide a broad perspective of eating disorders. These are not necessarily the views of Eating Disorder Hope, but an effort to offer discussion of various issues by different concerned individuals.

We at Eating Disorder Hope understand that eating disorders result from a combination of environmental and genetic factors. If you or a loved one are suffering from an eating disorder, please know that there is hope for you, and seek immediate professional help.

Reviewed By: Jacquelyn Ekern, MS, LPC on January 30, 2023
Published on EatingDisorderHope.com