Why I Care About Both Genes and Environment in Eating Disorders: The Anorexia Nervosa Genetics Initiative (ANGI) and AN25K

Human beings tend to like simple answers, but with eating disorders, it is clear that we need to embrace complexity in order to fully understand who is at risk and why. Simplistic biological explanations fail to acknowledge the toxic environmental factors that can contribute to the emergence and maintenance of eating disorders.

Purely sociocultural explanations neglect the rich science that has emerged over the past decades revealing clearly that biology in general and genetics more specifically play a substantial role in risk for eating disorders.

Adding even greater complexity, it is not just these two independent forces that influence eating disorders risk, but myriad ways in which genes and environment can act and co-act to both increase risk and to buffer someone from developing an eating disorder.


Cynthia Bulik, PhD, FAED shares why the ANGI project is being conducted. – As Posted By UNC Health Care

Even though the following explanation itself is too simplistic to reflect reality, I often talk with patients and family members about four general classes of risk and protective factors.

Genetic risk factors (those genes that increase your likelihood of developing an eating disorder), genetic protective factors (those genes that may buffer you against developing an eating disorder), environmental risk factors (environmental factors that increase your risk), and environmental protective factors (environmental factors that may buffer you from developing an eating disorder).

To fully understand anyone’s risk profile, you need to have a handle on all four of these quadrants. In addition, timing is important. An environmental insult that happens at age 7 might not influence your risk, whereas the same insult at 14, when you are smack in the middle of puberty, could trigger an underlying genetic predisposition.

At this point, there is nothing we can do about the genetic quadrants, we need to make due with the genetic cards we are dealt, so our prevention and treatment efforts all focus on the environmental quadrants.

We know that genes play a substantial role in anorexia nervosa, bulimia nervosa, and binge eating disorder, but we do not yet know which genes are implicated and how they act.

The Anorexia Nervosa Genetics Initiative (ANGI), funded by the Klarman Family Foundation, is the largest genetic study of anorexia nervosa ever conducted. ANGI unites researchers from the United States, Australia, Sweden, and Denmark to collect blood samples (for DNA) and clinical information on over 8,000 individuals who have had anorexia nervosa at any point in their lives and controls who have never had the disorder.

To boost the impact of ANGI, other countries have joined in an initiative called AN25K. Our goal is to collect 25,000 blood samples from women and men, girls and boys who have had anorexia nervosa by 2016! Most recently Charlotte’s Helix has emerged which will allow individuals throughout the United Kingdom to participate as well.

Some people might ask why we need so many samples, and truth be told, 25,000 is actually not even a large number in comparison to other studies in psychiatric genetics. We used to think that a few hundred participants were enough; we were proven wrong. Then we thought a few thousand were enough; again, we were proven wrong.

Now we know from observing the genetics of other psychiatric disorders that a sample size of around 10,000 starts being meaningful, but samples even larger than that have yielded concrete genetic findings.

For example, schizophrenia researchers have collected over 35,000 samples and by the end of the year will have >60,000! They have identified over 100 genes that influence risk for schizophrenia and neurobiologists are now working to understand precisely how those genes act to influence the complicated clinical features of that devastating illness.

Anorexia nervosa researchers currently have around 4,000 samples and we need to grow our sample size in order to reach the point where we too can start pinpointing the biology of the illness for which we are dedicated to finding the cause and the cure.

But identifying genes is only one benefit of genetic research. Even more importantly, genetic research can help us understand the role of the environment in a more nuanced fashion. How many times have we heard the question, “If everyone is exposed to the cultural thin ideal, why do we not all develop anorexia nervosa?”

Until now, it was just a rhetorical question. Once we identify individuals who are at high genetic risk who do and do not develop the disorder, we will be able to isolate which environmental factors release an underlying genetic predisposition and which help to silence it.

Our work will also allow us to identify those who may be at increased risk and consider how best to prevent the illnesses in those who are most genetically vulnerable.

I study the genetics of anorexia nervosa for several reasons.

  • First, anorexia nervosa is a devastating illness and there are no medications that are effective in the treatment of the disorder. Genetics has the potential to unveil new drug targets to tailor medications to the core features of the illness.
  • Second, labeling and stigmatization have plagued this field for far too long. Genetics allows us to sidestep old misconceptions about causes of eating disorders such as vanity or parenting styles that have hampered treatment and compassion for decades.
  • Third, far too many individuals have died or had their lives limited by the illness, and our ability to prevent the disorder is poor. If we can improve our prediction of who is at risk and save or improve even a handful of lives, our work will be worthwhile.

We hope that our success will be much greater and will allow us ultimately to ameliorate anorexia nervosa.

This is also just the first step. Parallel efforts for bulimia nervosa and binge eating disorder are emerging. Social media have brought researchers and participants together to join forces in making ANGI a success to surpass our AN25K goal.

We invite you to participate in this global effort.

  • If you are in the United States and you have had anorexia nervosa (at any point in your life), you can learn more or sign up with the Anorexia Nervosa Genetics Initiative (ANGI) study.
  • If you are in Australia, you too can participate by following this link. There is no travel necessary; you can participate in your hometown. Questionnaires are online and we send you your sample collection packet in the mail.

There are other ways you can contribute to this research. You can spread the word, via Twitter, via Facebook, and even pick up the telephone, to let people know about this critical effort to identify the genes that increase someone’s risk of developing anorexia nervosa.

If you have never had anorexia nervosa, you can also help. You can donate a blood sample as a control (that is, someone who has never had the illness).

Our eventual goal will be to compare the DNA of people who have had anorexia nervosa to the DNA of similar people who have never had anorexia nervosa to see where the differences lie. So we need your samples too!

ANGI participants are enthusiastic and giving. So many people we have spoken with are motivated by wanting to help others never have to experience what they went through. We invite you to join us in cracking the code of anorexia nervosa.

Article Provided By: Cynthia Bulik, PhD, FAED
Director, University of North Carolina Center of Excellence for Eating Disorders
Principal Investigator: Anorexia Nervosa Genetics Initiative (ANGI)

The opinions and views of our guest contributors are shared to provide a broad perspective on eating disorders. These are not necessarily the views of Eating Disorder Hope, but an effort to offer a 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.

Last Updated & Reviewed By: Jacquelyn Ekern, MS, LPC on November 12, 2015

Articles on Anorexia