Summary: New research from Brigham Young University reports that stress alters the gut microbiota of female mice in a way that mimics the effects of a high-fat diet.
Source: Brigham Young University
Stress may affect the gut as much as a poor diet, according to a new animal study.
A team led by Laura Bridgewater, a professor of microbiology and molecular biology at Brigham Young University (BYU), examined how stress interacts with diet to reshape gut microbial communities and influence behavior. Their findings, published in Scientific Reports, show a striking sex-specific effect: in female mice, stress shifted the gut microbiota composition to resemble that of mice fed a high-fat diet.
Bridgewater explains that stress is often considered chiefly a psychological issue, but it triggers measurable physical changes. “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,” she said. The study highlights how biological sex can influence the relationship between stress, diet, the microbiome, and behavior.
Study design: Researchers used groups of 8-week-old mice, assigning half of the males and half of the females to a high-fat diet for 16 weeks to induce obesity. After that dietary period, all mice underwent a series of mild, unpredictable stressors over 18 days. Throughout the experiment, investigators collected fecal pellets to analyze gut microbial DNA and observed anxiety-like behavior in an open-field arena to quantify activity and stress responses.
Key findings: The outcomes revealed notable differences by sex. Male mice consuming a high-fat diet showed increased anxiety-like behavior and reduced activity after stress more than females did. By contrast, female mice displayed a distinct microbial response: exposure to stress caused the gut microbiota of lean females to shift and more closely resemble the microbiota found in obese, high-fat-fed mice. In other words, stress alone produced in females a gut microbial profile similar to that produced by a high-fat diet.
Implications: Although this research was conducted in mice, the results are relevant for human health research. Women generally report higher rates of anxiety and depression, conditions linked to stress. Bridgewater suggests that differing stress-driven changes in gut microbiota may help explain some of the gender differences observed in mood disorders. The study underscores the importance of considering sex as a biological variable when investigating the gut–brain axis, obesity, and related mood disorders.
Contributors and context: The research included collaborators from Shanghai Jiao Tong University: Liping Zhao, Shengtian Li, Jing Wang, Qianpeng Zhang, Weiwei Hu, Yanqiu Wu, and Chenhong Zhang from BYU. The collaborative effort combined behavioral testing with high-throughput 16S rRNA gene sequencing to characterize changes in gut microbiota composition tied to diet and stress.
Publisher: NeuroscienceNews.com (summary reporting). Image source noted as public domain. Original research article: “Gender-based differences in host behavior and gut microbiota composition in response to high fat diet and stress in a mouse model” by Laura C. Bridgewater et al., published in Scientific Reports. DOI: 10.1038/s41598-017-11069-4.
Obesity is associated with a higher prevalence of mood disorders such as anxiety and depression. Both stress and a high-fat diet can alter the gut microbiota and contribute to obesity-related behavioral changes. In this study, obesity was induced in mice with a high-fat diet, and animals were later exposed to chronic unpredictable mild stress. Gut microbial composition was analyzed by 16S rRNA sequencing while anxiety-like behavior and activity levels were measured. Results showed distinct sex differences: male mice were more susceptible to anxiety-like effects of a high-fat diet and displayed reduced locomotion after stress, whereas in female mice, stress alone induced microbiota changes that resembled those caused by obesity. These findings emphasize the need to include sex as a biological variable when studying gut microbiota contributions to obesity-related mood disorders.
This summary reports the key methods and conclusions from the published animal study without adding new claims. The findings point to mechanisms worth exploring in human studies, especially regarding how stress and diet interact with sex-specific microbiome responses and mental health.