Which factors come to mind when you think about what dictates body image? More often than not, the pervasive mass media, pressure from society, Western standards of beauty, obsession with thinness, comparison to others, and perceived pressure from family or peers have been the long-standing influences. These standbys are also usually the first to blame for those times you look in the mirror and aren’t exactly over the moon about what you see, or how you feel in a pair of jeans (especially the fluorescent or printed ones that seem to be everywhere lately). Such is an example of the nature of negative body image that pervades us as a society today. The continual reinforcement of these ideals by the media—magazines, television, movies, advertisements, and glorification of celebrities—further compounds the problem. But questions remain: Why do only some people feel discomfort in their own skins? How do others seem entirely unconcerned? The answer to the varying feelings towards jeans may actually lie in our genes. Recent research has turned the spotlight to other factors that may be at play. Rather than focusing on the environmental factors that have long been recognized, a group of researchers supported by the National Institute of Mental Health took a look in the other direction, at the potential for an underlying genetic influence on thin idealization.
The pioneering study, published online in early October 2012 in the International Journal of Eating Disorders, was the first to look at whether genes influence body image, an unprecedented feat in itself, but these researchers took it up a notch by conducting a twin study, observing both identical and fraternal twins. They looked at the similarities and differences in body image in sets of twins raised both in the same and in different environments. More than 350 females participated in the study, ranging in age from 12 to 22, and were gauged on their desire to look like celebrities and other individuals commonly featured in magazines, television and movies using a detailed set of questionnaires. The major finding of the study indicated that identical twins were more likely than fraternal twins to have similar levels of thin idealization. Since identical twins are genetically identical and fraternal twins only share half of the same genes, differences between identical twins indicate an environmental factor at play, whereas similar results amongst identical twins points towards a genetic influence.
According to the study’s results, genetic influence on thin idealization is significant. This means that some people may be genetically predisposed to what the researchers refer to as “thin-ideal internalization,” which is simply a strong desire to attain thinness. The study estimates that this trait has a heritability estimate of 40%, a telling number, as it is closely aligned to the known heritability of disordered eating patterns, also hovering about 40%. The importance of this finding suggests that the thin-ideal internalization could be just as likely to develop as the serious and potentially devastating eating disorders that negative body image is sometimes known to preface. So how does this fit in with the vast array of information about how the environment impacts body image?
A concept known as the Tripartite Model proposes three general factors to be responsible for thin-ideal internalization that begins from outside influence: the media, parents and peers. The model explains that the quest for thinness and the tendency to make social comparisons serve as gateways to more serious consequences, namely disordered eating patterns and body dissatisfaction. The support behind the use of the model is substantial, with much research showing that if the desire for thinness is decreased, body image will improve to a similar degree. Essentially, this model and many others are established in the field, and account only for the “nurture” factors of the nature versus nurture paradigm. The next challenge will be to determine where these potential genetic factors fit into the environmental models used today to assess self-image.
Is it possible that these genetic predispositions are really personality traits manifesting themselves in different ways? There has long been a link between perfectionism and eating disorders, particularly anorexia nervosa, as well as the somewhat newer concept of ‘orthorexia,’ which is distinguished by a somewhat-manic desire to maintain a perfectly healthful diet. Certain personality traits, including perfectionism, are known to have a genetic link, meaning that the genetic factors responsible for personality may have a significant relationship with those in the study tentatively associated with thin-ideal internalization.
The bottom line is that a case has been made for nature in the ever-present argument of nature versus nurture except rather than one or the other, these two influences seem to exist in a synergistic balance. It is critical that more research is conducted on body image, especially at a time when the drastically skewed standards of thinness exalted by the media are inherently incorrect or unattainable. The continued study of body image will complement our understanding of the intricacies at play between genes and environment. Finally, focusing on strategies to defend positive body image, happiness and health against the onslaught of the media’s distorted images will ensure a better environment, less capable of damaging fragile self-images. Although these findings come from a single study that is the first of its kind, the strength of the data is promising for the path of future research on the influence genes may have on how we look and feel in our jeans and in our everyday lives.
*Sources available upon request
Kari Kempf is a first-year Friedman student in the Nutrition Communication program, aspiring to attain RD status. In her free time, she enjoys a balance of pumpkin pie and cycling/spinning, exploring her new New England home, and listening to Christmas music in October.