Myth # 8: Genes Are Destiny
In this eighth in a series of videos debunking nine myths about eating disorders, Cynthia Bulik, Ph.D., of the University of North Carolina, discusses evidence for environmental factors in eating disorders. The video was excerpted from a talk, "Eating Disorders Essentials: Replacing Myths with Realities," presented at the NIMH Alliance for Research Progress Winter Meeting, February 7, 2014 in Rockville, MD.
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>>Bulik: So the other thing we have to be careful about though is this sense that somehow genes are destiny. Because, I think, part of what I try to do in my world is figure out how best to take scientific information and convey it to the public and use it in therapy and to teach families and patients and advocates about how to talk about genetics--environment and genes are definitely not destiny. Hereditability for any of these disorders is not 100 percent. If environment didn't matter, heritability would be 100 percent. It's not. We’ve always got somewhere between 40 and 60 percent of variance that’s unaccounted for, and that's when we have to start looking at the environment--gene-environment interaction epigenetic factors. So for eating disorders, the environment can have both positive and negative influences. In terms of negative influences, environment can increase risk. Some of the things we know about—perfect timing given that the Winter Olympics are on: 1. Sports with an appearance or weight focus (Ski jumping—nasty. Ski jumping has completely changed how they do their sport to decrease the number of people who develop anorexia nervosa.) 2. Dieting--the number one thing that people talk about as the first step toward developing eating disorders is “going on a diet.” We have to be so careful in our obesity prevention efforts that we don't give people like me more business. We don't want our obesity interventions to create more eating disorders and that's why weight stigma and obesity stigma is such a concern. 3. Modeling--being obsessed with looks. We're finding out more and more that so many people with eating disorders have teasing or bullying histories--and not necessarily just about their physical appearance or their weight. But teasing is one of these nonspecific risk factors that I think we all see in our populations that many of these people have in their histories. But environment can also have positive influences. Some of the things that may decrease risk for the development of eating disorders: 1. Models for healthy eating—making sure that you really do model healthy eating, non-emotional eating, and making sure that your family is a place where healthy eating occurs. 2. Being able to separate body-esteem from self-esteem. The first thing people usually say about kids is what they look like. I always tell Moms, for example, if someone gives your child a compliment about especially her physical appearance, make sure you parrot right away with something like “Oh yeah, and she's also really great at playing the flute” or “She got an A in Chemistry” or something like that so your daughter is hearing more than just physical appearance–based compliments. 3. Role models for body respect. 4. Family Involvement. 5. Supportive peers who value who you are, not just how you look. 6. But also letting parents know that they can't control everything. You can have all the stuff in place and your child might still develop an eating disorder. Now this is one of the ways that I try to get people to understand the complexity of risk for an eating disorder. People like simple Yes-No, Black-White explanations, but we can't give them that. In fact, the truth is much more complex than the slide I'm going to show you. This slide at least breaks it down into four risk and protective quadrants and it's the way I like to help people think about what is changeable and what is not changeable. These are some very colorful human chromosomes. The first quadrant is genetic risk factors. So all of us are dealt a genetic hand of cards when we are born. The things that you see up here now are all things that we know are influenced by genetic factors. There’s not a gene for appetite regulation. There's not a gene for binge eating. But all of these things have been shown to be heritable. What that means is that there are probably a whole slew of genes that code for a whole slew of proteins that somehow influence that end phenotype. So the first quadrant is genetic risk factors. The second quadrant, and this gets to the resilience question that we were talking about before, are genetic protective factors. There are traits, for example, constitutional thinness or someone who never has to go on that first diet. We know self-esteem is influenced by genetic factors. How that works biologically I'm not so sure, but it is heritable. There are probably a whole slew of other protective factors that are influenced by genes. Your genetic deck of cards has both risk factors and protective factors. That then comes into the mix of the third quadrant, which are environmental risk factors. These are Shakespeare’s “slings and arrows about outrageous fortune” like teasing or dieting--things that are environmentally mediated that might actually have the ability to activate some of this underlying genetic risk. And then the fourth quadrant is environmental protection factors. Here we include: 1. Family meals-- because there have been a lot of data on family meals being protective against a whole array of adverse outcomes. 2. Breastfeeding--because breastfeeding is good for just about everything, and here, 3. This is a coach who was emphasizing strength and what your body can do rather than a sort of “thin to win” mentality. Everyone has a different pattern of genetic risk, genetic protection, environmental risk, and environmental protection quadrants. What matters is not just the relative balance of those four quadrants but also the timing. Some of these things might be--you might be more or less vulnerable to environmental activation, for example, during puberty or during menopause--so that sort of cross-cuts those four quadrants, the whole timing piece. And somehow people can often just begin to feel more comfortable with complexity if you can break it down into these four quadrants. But the other thing that you have to tell them is we can't do anything about the genes yet. The only thing we can do something about are the two environments. We can try to decrease the environmental insults and increase the environmental buffers.