Stress doesn’t only make you worried; it may also change your diet
Under stress, mice show atypical eating patterns that may indicate how stress affects the brain’s reward system, according to Frontiers in Neuroscience research.
It’s well known that stress affects hunger and food intake, but how it affects food choices and consumption habits is less clear. The researchers wanted to see whether these patterns may reveal more about stress’s effects on the brain than just food intake.
Little questions like why some people order the same cheeseburger or can’t stop eating potato chips led us to study feeding behavior processes beyond simple amounts.
Study author Shinsuke Ishigaki, a professor at Shiga University of Medical Science’s Molecular Neuroscience Research Center, stated overeating and starvation are still poorly understood despite being prevalent under stress.
Three stress models were used: social isolation, intermittent high-fat diet, and physical constraint:
These models reflect social, nutritional, and physical stress. Studies show that each of these stresses affects behavior and brain function.
Mice were isolated for a week to create anxiety without changing body weight for the social isolation experiment. The intermittent high-fat diet model gave mice a high-fat diet for a few hours every other day, which usually causes binge eating. The physical restraint paradigm immobilized mice for two hours a day for five days to simulate confinement stress.
The researchers created a real-time monitoring system to analyze how stress influenced eating.
They observed and recorded mice’s interactions with arena-based food sources using this method. Four bait containers were placed in a semi-circle, and mice may eat from any. The researchers utilized motion capture to detect how frequently and how long each mouse approached and ate from each container.
Researchers found “fixated feeding” in mice under all three stress settings. Stressed mice preferred one food source, unlike control mice, who ate uniformly across all food sources. This behavior was constant across all three stress levels, demonstrating that stress causes animals to focus on one food choice.
The results show that “changes in eating behaviors can reflect an individual’s environmental stress, whether obvious or not. The researchers analyzed dopamine levels in the nucleus accumbens shell, a reward system area, to determine the neurological basis of these changed behaviors.
In control mice, dopamine levels increased dramatically after feeding, demonstrating the usual reward response to food. In stressed mice, this dopamine response was greatly reduced or missing, showing that stress had damaged the brain’s reward system.
Furthermore, delivering dopamine directly into the stressed mice’s nucleus accumbens shell restored normal eating habits, supporting the concept that disturbed dopamine transmission caused abnormal behaviors.
The research also examined the dopaminergic circuit from the ventral tegmental region (VTA) to the nucleus accumbens shell, which controls brain reward and motivation. Researchers replicated stressed mice’s focused eating tendencies by selectively blocking this circuit using the DREADD technology. This revealed that eating habits are regulated by the mesolimbic dopamine system.
We were shocked to see that selective inactivation of VTA dopaminergic neurons caused focused feeding,” Ishigaki said.
Although the outcomes are compelling, the investigation has limitations. For one, mice were used, which are useful but not ideal models of human behavior. Stress affected eating patterns differently depending on the stressor, the researchers observed. The high-fat diet stressor raised appetites in some patients, whereas physical limitations dropped it, suggesting how multiple factors could influence eating behavior.
The researchers propose more studies on these issues, including whether individuals under stress exhibit comparable obsessed consuming inclinations.
They also recommend investigating how these eating practices are connected to other parts of the brain’s reward system and if they might predict psychological conditions like anxiety and depression.
Ishigaki said his long-term objective is to create a system that can identify small changes in eating habits. Deviations in eating behavior patterns may indicate stress and neuropsychiatric diseases including autism spectrum disorder and frontotemporal dementia.
Arshad Hussain