How Is the Brain of the Anorexic Women Different?

The obsession of these… 'living skeletons' for not gaining weight and the relentless pursuit of thinness may seem funny. But anorexia nervosa can lead to death in 10 % of the cases, besides the severe illnesses, due to the emaciation. Anorexia usually installs in adolescence, but it also appear throughout a woman's life, as they are 9 times more exposed to it than men are.

A new research found a clear biological factor behind the disorder, showing that this is not just psychological. Scientists suspected that patients of anorexia had impairments in the appetite controlling areas of the brain, but the new research made at the University of Pittsburgh and University of California, San Diego reveals that anorexic women have changes in the insula, the brain area involved in recognizing taste. This points to differences in the information linked to self-awareness in recovering anorexics when compared with non-anorexic patients.

The research team investigated the brain activity of 32 women through functional magnetic resonance imaging (fMRI.) 16 of them had recovered from anorexia nervosa and 16 were healthy control volunteers. The researchers assessed the brains' activations to pleasant taste (sugar) and neutral taste (distilled water).

The fMRI images clearly showed that anorexic women perceived the taste differently than healthy subjects did. The brain of anorexic women had a much more reduced reaction in the insula and its connected brain areas than in the control group. Insula and these other brain areas recognize taste and determine how rewarding a specific taste is. Also, the recovered anorexic subjects described the pleasantness of the taste to be much weaker than in the case of the healthy women.

"It is possible that individuals with anorexia have difficulty recognizing taste, or responding to the pleasure associated with food. Because this region of the brain also contributes to emotional regulation, it may be that food is aversive, rather than rewarding. This could shed light on why individuals with anorexia avoid normally "pleasurable" foods, fail to appropriately respond to hunger and are able to lose so much weight.", explained co-author Dr. Walter H. Kaye, of the UCSD.

"We know that the insula and the connected regions are thought to play an important role in interoceptive information, which determines how the individual senses the physiological condition of the entire body. Interoception has long been thought to be critical for self-awareness because it provides the link between thinking and mood, and the current body state. This lack of interoceptive awareness may contribute to other symptoms of anorexia nervosa such as distorted body image, lack of recognition of the symptoms of malnutrition and diminished motivation to change," said Kaye.