A joint study just released by the University of Pittsburgh and University of California, San Diego shows that women with anorexia nervosa also have differences in the part of the brain that plays an important part in recognizing taste, called the insula.
Anorexia nervosa can result in death in about 10% of the cases. It usually first appears in adolescence, but it can strike at any time in a person’s life span. It is also nine times more likely to affect women than men. This alone shows that there may be a biological process that contributes, at least in some part, to the disorder.
The study also indicates that there may also be differences in the way a person who is recovering from anorexia nervosa processes the information related to self awareness as compared to those who do not have the illness. They hope that the results of this study will lead to a better understanding of just what causes the disease.
In the survey, they measured the brain activity of 32 women with functional magnetic resonance imaging (fMRI.) There were two groups with 16 of the women having recovered from anorexia nervosa and 16 control subjects who had not had the disease. The women’s brains were measured for their reaction to a pleasant taste, represented by sucrose and a neutral taste, represented by distilled water. This is the first study that shows patients with anorexia do actually process tastes in a different way.
The results were the same to both substances. Those who had recovered from anorexia had a significant reduction in the response from the insula as well as other related areas of the brain. All of these areas are responsible for recognizing a taste and then assessing how pleasant that taste is to the person. Those in the control group showed a very strong relationship between their perception of how pleasant the taste was and the activity of in insula, but those in the anorexia group did not.
The researchers feel that this shows people with the disorder have difficulty recognizing taste and/or they cannot respond to the pleasures associated with food. Also, this is the part of the brain that plays a part in regulating emotion and this shows that the patients may see food as something to dislike instead of as something to get pleasure from. This is manifested in the fact that those with anorexia avoid what everyone considers to be pleasurable foods and fail to respond to hunger in an appropriate manner and thereby lose such a large amount of weight.
They have known that the insula and the other related parts of the brain probably play important roles in the process of interoceptive information, which is the determination of how the person senses the physiological condition of the entire body. This has, for a long time, been thought to play an important part in a persons self awareness because it provides the link between thinking and mood, and the current body state
The study was led by Angela Wagner, M.D., University of Pittsburgh School of Medicine, and Walter H. Kaye, M.D., of the University of Pittsburgh and the University of California, San Diego (UCSD) Schools of Medicine
Co-authors of the study include Howard Aizenstein, Laura Mazurkewicz and Lorie Fischer of the University of Pittsburgh School of Medicine; Julie Fudge of the University of Rochester Medical Center; Guido K. Frank of the University of Pittsburgh School of Medicine and University of California, San Diego; Karen Putnam of the University of Cincinnati; and Ursula F. Bailer of the University of Pittsburgh School of Medicine and Medical University of Vienna.
The research was funded through grants from the National Institute of Mental Health and the Price Foundation.
Source: USC San Diego http://health.ucsd.edu/