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Stress contributes to disturbed eating behavior
Stress has a negative impact on our eating habits and can lead to impaired food intake. Researchers now wanted to find out why this is so and what can be done about it.
The University of Texas' latest study found how stress can contribute to eating disorders. The results of the study were published in the English language journal "Nature Communications".
Stress inhibits the urge to eat in mice
Many people are not hungry under stress and other strong emotional states. Researchers are now trying to find out how the brain causes these emotion-related effects on eating behavior. In doing so, they discovered a previously unknown brain path in mice that can be stimulated to increase the level of stress in the animals and at the same time reduce their urge to eat. The study examined a neural circuit that connects two mouse brain regions, the paraventricular hypothalamus (PVH) and the ventral lateral septum (Lsv). The first region is related to feeding, the second to emotional regulation. The examined brain circuit is used to switch the signal path on and off. The activation of this cycle shows a measurable and dose-dependent effect on eating in relation to emotional stress, explains the research group.
Results could improve treatment for anorexia nervosa
The paraventricular hypothalamus is a central point for the coordination of adaptive behavior and bodily functions that are important for our survival, including eating. The study found that both PVH and LSv neurons are sensitive to environmental stimuli. On the other hand, they were relatively inactive during the feeding activity of the mice. However, a part of the brain was identified in the mouse model that controls the influence of emotions on food, the researchers report. This understanding could offer a way to treat, for example, the eating disorder called anorexia nervosa. This eating disorder kills more people than any other mental illness, the researchers report on figures from the National Institute of Mental Health.
Wrong self-perception in anorexia nervosa
Diagnostic features of anorexia nervosa are the intake of severely restricted amounts of food and a completely distorted body image. A classic finding in anorexia nervosa is, for example, the feeling that you are fat, even if the person is actually far too thin and is already below the minimum limit for a healthy body weight. Older studies have already shown that stress has a strong influence on increasing and reducing the urge to eat, the researchers explain. So far, however, it has not been possible to determine how exactly this interaction occurs.
Stressed mice eat less
During the investigation, the researchers used so-called optogenetic techniques to activate and inhibit the neural circuit. They found that when the circulatory system was activated, the neurons released glutamate, with a corresponding increase in anxiety levels, while appetite (depending on the dose) decreased. With poor light stimulation, the mice began to groom themselves, a classic stress response. Strong light stimulation created an escape behavior known to be related to fear. This indicated that the electrical activity between PVH and Lsv modulates emotional states, which also changes eating behavior. The activation also caused an inhibition of food intake, even when there was hunger. This showed how eating disorders can be related to mental changes. This is consistent with previous evidence that an animal's sense of security or stress competes with its eating behavior. In other words, animals eat more if they are not stressed out by a feeling of danger.
Common brain circulation for nutrition and emotions?
The results also led the researchers to consider the possibility of a common brain circulation, which underlies the regulation of both nutritional and emotional states. It is already known that areas such as the amygdala are crucial for regulating emotions. Similarly, the transmission of one type of neuron in the hypothalamus causes more hunger, while another type inhibits eating, the researchers sum up. (as)
Author and source information
This text corresponds to the specifications of the medical literature, medical guidelines and current studies and has been checked by medical doctors.
- Yuanzhong Xu, Yungang Lu, Ryan M. Cassidy, Leandra R. Mangieri, Canjun Zhu et al .: Identification of a neurocircuit underlying regulation of feeding by stress-related emotional responses, in Nature Communications (query: 19.08.2019), Nature Communications