A molecule may represent the brain link between stress and emotional eating, linking threatening experiences to the desire to eat too many high-fat foods, according to a Virginia Tech study
If you’ve almost been in a car accident or been intimidated by a threatening person, you’ve probably felt it: a psychological reaction to a threat called the fight-or-flight response. Your heart rate increases, anxiety overcomes you, and you shake or sweat.
But hours after the stress has passed, you may experience a different reaction: a strong craving for comfort foods—that is, highly processed, high-fat foods that you know aren’t good for you. It can relieve stress and tension and provide a sense of control. Many of us, including scientists, are familiar with emotional eating after a stressful interaction.
Until now, however, it was unknown how threat causes the brain to want comfort food.
Now a Virginia Tech scientist has identified a molecule found in a region of the brain called the hypothalamus that is linked to brain changes that lead to emotional overeating. Sora Shin, assistant professor at the Fralin Biomedical Research Institute at VTC, and his research team described the discovery in a paper published Oct. 28 in Nature Communications.
The emotional eating molecule
“We don’t always eat because we are hungry and have certain physical needs,” said Shin, who is also an assistant professor in the Department of Human Nutrition, Nutrition and Exercise in Virginia Tech’s College of Agriculture and Life Sciences “When we are stressed or Feeling a threat can also trigger our motivation to eat.” “We think this molecule is the culprit.”
Shin and his research team began their study by examining a small molecule, proenkefalin. This molecule is found in several parts of the brain, but its role in the hypothalamus has been poorly understood. Shin suspected that it played a role in stress and eating, since the hypothalamus is a center that regulates eating behavior.
The lab exposed mice to the smell of cat feces. The smell of a natural predator triggered a threat response in the mice, and 24 hours later the mice exhibited a negative emotional state, overeating behavior, and the neurons in their brains became sensitive to eating high-fat foods.
To confirm the molecule’s role in stress-induced feeding, the researchers artificially activated the same neurons with light that stimulated a genetically encoded molecule expressed on the neuronal cell membrane, without the smell of the predator, and observed a similar response. In addition, when they exposed the mice to the smell of cats and silenced the response of neurons expressing this molecule using the same technique, the mice did not show a negative emotional state or overeat.
“So something in this molecule itself is very crucial in triggering overconsumption after the threat,” Shin said.
The discovery suggests a possible therapeutic target to alleviate emotionally triggered eating.
“We still have a lot to learn about this molecule,” Shin said, “but we have found its location and it could be a good starting point.”
Lateral hypothalamic proenkephalin neurons control threat-related overeating associated with a negative emotional state