From adolescence to young adulthood, females are at the greatest risk of developing eating disorders. Aside from age and gender, however, scientists have discovered other, more complex biological causes of eating disorders. A number of studies have shown that certain types of brain activity appear to be characteristic of individuals with eating disorders.
Biological Factors in the Brain: Serotonin
Serotonin is a chemical messenger, or neurotransmitter, in the brain. A study published in The American Journal of Psychiatry (2001) reported that serotonin levels might be one of the biological causes of bulimia. After comparing serotonin in women who had recovered from bulimia nervosa with those who hadn’t had the disorder, they found abnormal serotonin levels in those who had suffered from the condition.
Serotonin levels may also influence how people eat, playing a role in the development of eating disorders, according to scientists from the Mayo Clinic (2010).
Brain Protein Biological Factors
Brain-derived neurotrophic factor (BDNF) is a protein in the brain that promotes the growth and survival of neurons in the central and peripheral nervous systems. In a study published in the journal Psychological Medicine (2009), researchers reported that individuals with anorexia nervosa had lower levels of this protein than women who had never had anorexia or those who recovered from the disorder. Scientists found that women with low levels of BDNF also suffered from anxiety, depression and low self-esteem–all three risk factors for developing anorexia.
Other Biological Factors in the Brain
Other studies demonstrate that individuals with eating disorders may display abnormal activity in certain areas of the brain. Individuals with anorexia nervosa may exhibit abnormal levels of activity in the areas that influence decision-making and learning from experience, according to researchers with the University of Pittsburgh (2005). These scientists also state that individuals with bulimia nervosa show greater than average activity in the reward regions of the brain.
Birth Complications and Biological Eating Disorders
Prenatal and postnatal problems may also increase the risk of developing eating disorders later in life. Italian researchers found that prenatal complications influence eating disorders by affecting the development of the brain and nervous system in the fetus, according to a study published in the Archives of General Psychiatry (2006). Additionally, proper prenatal and postnatal nutrition appear to impact nutrition even in adult life.
Treatment for Eating Disorders?
At present, there’s no pharmaceutical drug for the treatment of anorexia, bulimia or binge eating disorder. Although antidepressants may facilitate treatment in some individuals, a thorough understanding of the biological causes of eating disorders is necessary in order to develop treatments that target the biological factors specific to eating disorders.
Faculty of 1000: Biology and Medicine (2009). A biomarker for anorexia? Retrieved July 11, 2010, from http://www.sciencedaily.com/releases/2009/06/090623111949.htm
Favarro, A., Tenconi, E. & Santonastaso, P. (2006). Perinatal factors and the risk of developing anorexia nervosa and bulimia nervosa. Retrieved July 12, 2010, from http://archpsyc.ama-assn.org/cgi/content/full/63/1/82
Kaye, W. H., Frank, G. K., Meltzer, C. C., Price, J. C., McConaha, C. W., Crossan, P. J.,… & Rhodes, L. (2001). Altered serotonin 2A receptor activity in women who have recovered from bulimia nervosa. Retrieved July 10, 2010, from http://ajp.psychiatryonline.org/cgi/content/full/158/7/1152
Mayo Clinic (2010). Eating disorders. Retrieved July 8, 2010, from http://www.mayoclinic.com/health/eating-disorders/DS00294
National Eating Disorders Association. (2004). Factors that may contribute to eating disorders. Retrieved July 8, 2010, from http://www.nationaleatingdisorders.org/uploads/file/information-resources/Factors%20that%20may%20Contribute%20to%20Eating%20Disorders.pdf
Nakazato, M., Tchanturia, K., Schmidt, U., Campbell, I. C., Treasure, J., Collier, D. A. … & Iyo, M. (2009). Brain-derived neurotrophic factor (BDNF) and set-shifting in currently ill and recovered anorexia nervosa (AN) patients. Retrieved July 10, 2010, from http://www.ncbi.nlm.nih.gov/pubmed/18752728
University of Pittsburgh Medical Center. (2005). Specific regions of brain implicated in anorexia nervosa, finds Univ. of Pittsburgh study. Retrieved July 11, 2010, from http://www.sciencedaily.com/releases/2005/07/050708055534.htm