A new University of Colorado Boulder study has found that anxiety, as well as other mental health disorders, could be linked to the food we eat.
Christopher Lowry, a professor of integrative physiology at CU Boulder, was part of a team who studied the effects and behavior of male rats with high-fat diets. The experiment worked to expand the information and findings in a new field of psychology that focuses on nutrition.
“(Nutritional psychiatry) is really exciting because they are finding that all dietary changes can improve depression and anxiety symptoms.” Lowry said.
The experiment tested two adolescent male rat groups, giving one group a diet of 11% fat and giving the other group a diet of 45% fat. The typical American diet is about 36% fat.
The rats were observed and fed for nine weeks before Lowry and his team performed behavioral tests on them. Aside from the obvious weight gain, the team did notice a the high-fat diet group had a larger percentage of several genes associated with producing serotonin.
While serotonin is often billed as a “feel-good brain chemical,” Lowry said that certain subsets of serotonin neurons can, when activated, prompt anxiety-like responses in animals. Notably, heightened expression of TPH2, or tryptophan hydroxylase, one of the genes identified in the study, has also been associated with mood disorders and suicide risk in humans.
“We saw that with the high-fat diet we were able to see this emergence of a molecular signature of anxiety after several weeks, which suggest that there is something really hardwired about the relationship between diet and neural systems in the brain that are involved in controlling anxiety, including the serotonin system,” Lowry said.
The connection between the stomach and brain still requires much more research. Through other studies as well as this one, it is hypothesized that there is an ability for bacteria in high-fat foods to break through a gut lining and infiltrate brain chemicals.
“We think that may involve changes in the gut lining that over time allow bacteria to get into the body and then that drives the inflammation,” Lowry said. “We’re still working on understanding how those early changes in the gut microbiome lead to later changes in inflammation that maybe drives mental health effects.”
The experiment has continued to work on the much larger question about the relationship between food and mental health, and how more information could inform eating habits.
“We tend to think that the impacts of unhealthy eating are limited to weight gain … but if people realize it also has impacts on the brain and mental health conditions, then the stakes are much higher.” Lowry said.
For more information on the study visit biolres.biomedcentral.com/articles/10.1186/s40659-024-00505-1.
