Stomach Nerves Function as 'Clock' Regulating Eating Habits

Nerves in the stomach likely function as an internal "clock," relying on the circadian rhythm to regulate our food intake to certain times of day, according to a research team from the University of Adelaide.

Writing in The Journal of Neuroscience, the research team reports that further study on our stomach's clock could lead to a better understanding of how the gut signals our brain to inform it when we are full and when we need to keep on eating.

Lead study author Stephen Kentish, of University of Adelaide's Nerve-Gut Research Laboratory, investigated how the nerves in the stomach respond to stretch, which occurs as a consequence of food intake at approximately three-hour intervals throughout the day.

"These nerves are responsible for letting the brain know how much food we have eaten and when to stop eating," Kentish said. "What we've found is that the nerves in the gut are at their least sensitive at time periods associated with being awake. This means more food can be consumed before we feel full at times of high activity, when more energy is required.

"However, with a change in the day-night cycle to a period associated with sleeping, the nerves in the stomach become more sensitive to stretch, signaling fullness to the brain quicker and thus limiting food intake. This variation repeats every 24 hours in a circadian manner, with the nerves acting as a clock to coordinate food intake with energy requirements," he said in a statement.

Kentish and his colleagues' work is based on laboratory studies, not on human tests.

"Our theory is that the same variations in nerve responses exist in human stomachs, with the gut nerves being less sensitive to fullness during the day and more sensitive at night," Kentish said.

Amanda Page, another researcher involved in the study said the research could lead to more information on how changes in people's circadian clocks affects their eating habits.

"We know that shift workers, for example, are more prone to disruptions in sleep and eating behavior, leading to obesity and other health problems. We are now conducting further research to see what kind of impact such changes to the circadian rhythm will have on eating behavior, and how the nerves in the stomach react to those changes," Page said.