For some women, genes may influence pressure to be thin

Genetics may make some women more vulnerable to the pressure of being thin, a study published in the International Journal of Eating Disorders has found. From size-zero models to airbrushed film stars, thinness is portrayed as equaling beauty across Western culture, and it's an ideal often cited as a cause of eating disorder symptoms in young women.

The researchers focused on the potential of women buying into this perceived ideal of . Changes in self-perception and behavior, caused by this idealization, can lead to , a preoccupation with weight and other symptoms of eating disorders.

"We're all bombarded daily with messages extoling the virtues of being thin, yet intriguingly only some women develop what we term thin ideal internalization," said Jessica Suisman, lead author on the study and a researcher at Michigan State University (MSU). "This suggests that may make some women more susceptible to this pressure than others."

To explore the role of genetic factors in whether women "buy in" to the pressure to be thin, the idealization of thinness was studied in sets of twins. More than 300 female twins from the MSU Twin Registry, ages 12-22, took part in the study. The team measured how much participants wanted to look like people from movies, TV and magazines. Once the levels of thin idealization were assessed, identical twins who share 100 percent of their genes were compared with fraternal twins who share 50 percent.

The results show that have closer levels of thin idealization than fraternal twins, which suggests a significant role for genetics. Further analysis shows that the of thin idealization is 43 percent, meaning that almost half of the reason women differ in their idealization of thinness can be explained by differences in their genetic make-up.

In addition to the role of genes, findings showed that influences of the environment are also important. The results showed that differences between twins' environments have a greater role in the development of thin ideal internalization than wider cultural attitudes, which women throughout Western societies are exposed to.

"We were surprised to find that shared environmental factors, such as exposure to the same media, did not have as big an impact as expected," Suisman said. "Instead, non-shared factors that make co-twins different from each other had the greatest impact."

Although the study did not look at specific environmental triggers, non-shared environmental influences typically include experiences that twins do not share with one another. This could include involvement by one twin in a weight-focused sport like dance, one twin being exposed to more media that promotes thinness than the other, or one of the having a friendship group that places importance on weight.

"The broad cultural risk factors that we thought were most influential in the development of thin-ideal internalization are not as important as genetic risk and environmental risk factors that are specific and unique to each twin," said Suisman. Kelly Klump, MSU professor of psychology and co-author on the study, said it is well established that a broad range of factors can contribute to the development of eating disorders.

"This study reveals the need to take a similar approach to the ways in which buy in to pressure to be thin, by considering how both genetic and environmental factors contribute to the development of thin-ideal internalization," Klump concluded.

More information: Suisman, J, Sperry. S, Thompson. J, Keel. P, Burt. S, Neale. M, Boker. S, Sisk. C, Klump. K, "Genetic and Environmental Influences on Thin-Ideal Internalization", International Journal of Eating Disorders, September 2012, DOI:10.1002/eat.22056

add to favorites email to friend print save as pdf

Related Stories

Fainting: All in the family?

Aug 06, 2012

Fainting has a strong genetic predisposition, according to new research published in the August 7, 2012, print issue of Neurology, the medical journal of the American Academy of Neurology. Fainting, also called vasovagal syncop ...

Genes an important factor in urinary incontinence

Apr 04, 2011

Much of the risk of developing incontinence before middle age is determined by our genes. Genetic factors can explain half of people's susceptibility to urinary incontinence, a study of twins at the University of Gothenburg ...

Recommended for you

Brains transform remote threats into anxiety

Nov 21, 2014

Modern life can feel defined by low-level anxiety swirling through society. Continual reports about terrorism and war. A struggle to stay on top of family finances and hold onto jobs. An onslaught of news ...

Mental disorders due to permanent stress

Nov 21, 2014

Activated through permanent stress, immune cells will have a damaging effect on and cause changes to the brain. This may result in mental disorders. The effects of permanent stress on the immune system are studied by the ...

Could there be a bright side to depression?

Nov 21, 2014

(Medical Xpress)—A group of researchers studying the roots of depression has developed a test that leads them closer to the idea that depression may actually be an adaptation meant to help people cope with ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.