The hypothalamus is responsible for the hunger drive of the human body. This part of the brain connects the endocrine system to the nervous system. Leptin and ghrelin, the two hormones most connected with hunger, both have receptors in the hypothalamus. Ghrelin, produced by the stomach, is thought to signal hunger. Levels of this hormone are low after meals, and high before. On the contrary, leptin, produced in adipose tissue, signals satiety.
However, this system does not always work perfectly. Eating disorders are thought to be partially due to hypothalamic disorders. Studies of people with bulimia show that they may not have a satiated response after eating a meal. In other words, their brains do not receive the signal that they have finished eating. However, it is unclear which or even if any hormones play a role in eating disorders, although there are other biological factors involved. New research may shed light on the brain pathways involved in eating disorders.
In women with anorexia nervosa or bulimia, signals from the hypothalamus were “overriden” by other parts of the brain. Structural differences were found in white matter associated with taste-reward and appetite regulation. This suggests that these parts of the brain communicate differently in those individuals with eating disorders. According to one of the authors of the study, this correlated to food not being interpreted as a reward. Rather, it leads to weight gain, making it a punishment.
However, this study does have a few limitations. Binge eating disorder was not covered, and only women were tested. The authors also wish to look at the brains of children, as a way to effectively determine when these changes are initiated. Nevertheless, the study sheds not only sheds light on neural mechanisms of eating disorders, but it may also suggest treatment in the form of behavioral therapies.
Note: If you or someone you know is struggling with an eating disorder, we encourage you to seek help. Please call the National Eating Disorders Association hotline at 1-800-931-2237, or visit their website to find support in your area.
Editor: Johnny Armenta