The Role of Genetics in Eating Disorders

When discussing eating disorders, the role of the media often surfaces in the conversation. Many experts and eating disorder patients believe that the images of physical perfection flooding the television and print media provide an impossible ideal that women cannot reach. The comparison between oneself and an unrealistic image of a celebrity can lead to body dissatisfaction, a precursor to body image distortion, a symptom of eating disorders. However, some women view the images and struggle to maintain a healthy body image, while others view the images and turn away unchanged. While environmental influences, such as media images and family history, are important risk factors for eating disorders, researchers at Michigan State University wanted to find out why certain women seem predisposed to body image struggles. The study, available in a recent issue of the International Journal of Eating Disorders, examined the psychological effect on women who believe in the thin ideal promoted in the media. Lead author Jessica Suisman explains that all women are hit consistently and constantly with the merits of thinness and yet only certain women develop something called thin ideal internalization. Believing that genetics must play a role in how women are affected by the culture’s pressure to be slim, the researchers studies the idealization of thinness in 300 female twins from the MSU Twin Registry. The twins were all between the ages of 12 and 22. The researchers examined the level at which the participants desired to look like celebrities from television and magazines. After measuring thin idealization in the twins, the results were measured comparing the results among identical twins, who have 100 percent of their genes which are the same with that of fraternal twins, who have 50 percent of their genes which are the same. The analysis revealed that the identical twins more closely had the same levels of thin idealization when compared with the fraternal twins, providing support for a significant genetic role in thin idealization. The heritability of this trait was 43 percent, showing that genetics can explain nearly half of why women differ in thin idealization. Not surprisingly, the results also conveyed that the environment plays a significant role in how the pressure to be thin is processed by individuals. The results showed that differences in the twins’ environments made an impact in their differences in thin idealization, providing evidence that specific environments are more influential than wider cultural values about thinness. Suisman says that the researchers were surprised to discover that wide cultural influences, such as exposure to similar media, was not as influential as expected. Rather, the non-shared environmental factors had the most significant impact. The study’s findings reinforce the belief among experts that while each eating disorder case is the result of a unique combination of risk factors, it is well-established that both genetic and environmental factors play a major role.