When you get hungry, you're motivated to find food and eat. Years of evolution have ingrained this basic survival skill into us. But it isn't quite this simple for people suffering from anorexia, who will endure long periods of intense hunger and still avoid food. In the past, this disconnect has been seen as a matter of willpower or rebellion but a new study says it's actually a genetic problem. And, in a breakthrough for eating disorder sufferers everywhere, scientists say they've found a gene that may be responsible for causing anorexia.
Past studies have shown there is a strong genetic component to anorexia—it's estimated that 50 to 70 percent of eating disorders can be chalked up to our genes. Now, researchers have found pinpointed the problematic piece of DNA. It all comes down to a missing estrogen-related receptor alpha (ESRRA) gene, says lead study author Michael Lutter, M.D., Ph.D., assistant professor of psychiatry in the University of Iowa. His research found that without the gene, mice are less likely to find food when they are hungry. They also have abnormal social interactions, becoming isolated and withdrawn from the group, mimicking the characteristics of humans with anorexia, he explains. (It's not just about starving yourself, though. Read about one woman's Fight with Orthorexia: How Healthy Habits Turned into an Eating Disorder.)
"Like most complex illnesses, there are probably many genes that are involved in the risk of developing an eating disorder," Lutter says. "The mutation that we found in ESRRA, is rare (affecting only about one in every 10,000 people), but does seem to give you a very high chance of developing an eating disorder—perhaps as high as 90 percent, although it's hard to tell until we find more people with the mutation [to study]."
The study also found that, while the gene appears to effect behavior, lifestyle and behavioral choices also seem to affect the gene itself. Lutter explains that the gene can be turned on by "states of increased energy demand" like excessive exercise or starvation. Most people feel hunger and look for food in those situations, but those with the gene do not respond properly to hunger cues once it's turned "on," thanks to the decreased amount of ESRRA. And while the scientists didn't come out and say it, we have to wonder if our Western thinner-is-better ideal could be causing women with the gene to unintentionally flip it to on and start the eating disorder cycle by encouraging relentless dieting and extreme exercise. (Like these 5 Common Body Goals That Are Unrealistic.)
Interestingly, this willingness to starve was more pronounced in female mice—which might help explain why women are much more likely to suffer from the illness than men. "There are a number of links between estrogen and ESRRA," Lutter explains. "Female mice lacking the ESRRA gene are more severely affected than male mice, which suggests that estrogen receptor signaling is important for the effects of ESRRA, but its not clear exactly yet how that works." He adds that the female mice also showed increased obsessive-compulsive-like behaviors, another key component of eating disorders. (Does Your Boyfriend Have An Eating Disorder?)
Lutter cautions that much more research needs to be done, but he is hopeful this will lead to better, more effective treatments for anorexia. In addition to preventative behavioral treatments—there is hope that people can avoid triggering the gene by practicing a moderate diet and exercise routine—he sees the potential for drugs that target ESRRA production.
All of this is great news for sufferers of anorexia, the mental illness with the highest mortality rate and one of the lowest treatment success rates. And perhaps this will also reduce the stigma that many eating disorder sufferers face by showing that this is an illness with a biological basis, just like diabetes or cancer, rather than a moral failing or sheer stubbornness.
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