Two sides of the same coin: High fat diets cause anxiety and stress causes digestion problems

A new study from Brigham Young University (BYU) reveals that digestive microorganisms change behavior when the host is under stress.

BYU professor of microbiology and molecular biology Laura Bridgewater used male and female mice for the study experiment. She found that when the female mice were exposed to mild stress, their gut microbiota (microscopic organisms vital to digestive and metabolic health) changed as if the host was consuming a high-fat diet.

Bridgewater and her collaborators at Shanghai Jiao Tong University in China took a large group of eight-week-old mice and exposed half of the males and half of the females to a high-fat diet. After 16 weeks, all the mice then underwent mild stress in the form of forced swim test and the tail suspension test over the course of 18 days.

The researchers studied the microbial DNA extracted from the mice fecal pellets before and after the stress test to look for distinct changes in the microbiota. They also measured the anxiety levels of the mice based on how much they traveled in an open field arena.

The results revealed that male mice on a high-fat diet showed more anxiety than the females of the same group. The males of this group also showed a decrease in activity in response to stress. However, only the microbiota of the female mice displayed changes after undergoing stress, seemingly behaving as if the hosts were on a high-fat diet.

“Stress can be harmful in a lot of ways, but this research is novel in that it ties stress to female-specific changes in the gut microbiota,” Bridgewater said. “We sometimes think of stress as a purely psychological phenomenon, but it causes distinct physical changes.”

The research gives a new perspective on the symptoms that people, particularly women, manifest when under considerable amounts of stress. While stress can be triggered by many factors, studies showed that lack of sleep is one of its major drivers. In some studies, stress has been found to affect blood sugar levels and increase the risk of gestational diabetes in women.

Bridgewater’s research was only conducted on animals, but she and her colleagues believe the results could have significant relevance to human digestive and metabolic functions. (Related: 5 reasons your digestive system isn’t working properly.)

“In society, women tend to have higher rates of depression and anxiety, which are linked to stress,” said Bridgewater, who also serves as Associate Dean of the BYU College of Life Sciences. “This study suggests that a possible source of the gender discrepancy may be the different ways gut microbiota responds to stress in males vs females.”

We all know that poor diet is harmful to overall health, but this study helps shed light on the role that stress may play in causing digestive problems in humans.

The study was published in Nature Scientific Reports.

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Sources include:

ScienceDaily 1

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