Hunger Hormone Influences Comfort Eating when Stressed
The term “comfort food” is used to describe something that is consumed that seems to improve emotional status. It was first coined in 1977 and is divided into four subcategories – nostalgic food, indulgence foods, convenience foods and physical comfort foods. The foods that we choose as a coping mechanism to stress (the physical comfort foods) may not be all in the brain, but could be influenced by ghrelin, also known as the “hunger hormone”.
Study Narrows Down Reasons Why We Eat Fatty Food When Stressed
The ingestion of comfort food has been studies as a contributory factor to the obesity epidemic. Previous research by Mary Dallman et al at The Rockefeller University found that during stressful situations, certain hormones increase the tendency toward pleasurable or compulsive activities, such as ingesting comfort foods consisting highly of sucrose (sugar) and fat.
New research, led by Dr. Jeffrey Zigman, an assistant professor of internal medicine and psychiatry at UT Southwestern Medical Center, drills down to one of these hormonal pathways, focusing on ghrelin which is released from the gastrointestinal tract and plays a role in sending hunger signals to the brain. Chronic stress has been shown to increase ghrelin levels and behaviors that are associated with depression and anxiety are minimized when ghrelin levels rise.
Zigman and colleagues developed a mouse model to study the effects of ghrelin on overeating and weight gain during stressful times. They subjected the nice to a standard laboratory technique that induces social stress by exposure to more dominant “bully” mice. The mice subjected to stress gravitated toward a chamber where they were trained to find pleasurable, fatty foods. Genetically engineered “control” mice, those who were not able to respond to stress-induced ghrelin, showed no preference toward the mouse “comfort foods.”
The study also showed that the effects of ghrelin are due to interaction with a subset of neurons that use catecholamines as a neurotransmitter. These include the dopaminergic neurons in the brain’s ventral tegmental area, which is known to be associated with pleasure and reward behaviors.
“Our findings show that ghrelin signaling is crucial to this particular behavior and that the increase in ghrelin which occurs as a result of chronic stress is probably behind these food-reward behaviors,” Dr. Zigman said, writing in the Journal of Clinical Investigation. “This helps explain certain complex eating behaviors and may be one of the mechanisms by which obesity develops in people exposed to psychosocial stress.”
This new finding may lead to the development of new therapeutic measures to treat and/or prevent obesity, Dr. Zigman concludes.