Women’s Gut Bacteria Linked to Emotional Regulation
Innovative research from Brigham and Women's Hospital and the Harvard T.H. Chan School of Public Health has uncovered a connection between the gut microbiome and positive emotions like happiness, hopefulness and better emotional management skills. The study's results, which contribute to a growing body of research on the relationship between the gut microbiome and mental health, were recently published in the journal Psychological Medicine.
Emotional axis
The gut–brain axis, a communication pathway between the brain and the gastrointestinal tract, has garnered significant attention from the scientific community in recent years. One prevailing theory suggests that the gut microbiome, consisting of trillions of microorganisms, plays a pivotal role in this axis, linking physical and emotional health.
Dr. Yang-Yu Liu, an associate scientist in the Brigham's Channing Division of Network Medicine and an associate professor of Medicine at Harvard Medical School, explained the importance of the gut microbiome. He stated that many studies have shown that disturbances in the gut microbiome can impact the gut-brain axis and lead to various health problems, including “anxiety, depression, and even neurological disorders.”
Dr. Shanlin Ke, the first author of the study and a postdoctoral researcher in Liu's lab, highlighted that the interaction between the brain and the gut likely flows both ways. Emotions and how they are managed can affect the gut microbiome, and the microbiome may, in turn, influence how individuals feel.
Notably, the gut-brain axis might additionally impact physical health. Previous research has demonstrated that positive emotions and healthy emotional regulation are linked to greater longevity, whereas negative emotions are associated with higher rates of cardiovascular disease and mortality from all causes, according to Dr. Laura Kubzansky, a study co-author and professor of Social and Behavioral Sciences at the Harvard T.H. Chan School of Public Health.
Reappraisal and suppression
The new study included more than 200 women from the Mind-Body Study, a sub-study of the 100,000-participant Nurses' Health Study II, a massive women’s health project that began in 1989. These middle-aged, predominantly white participants completed a survey that inquired about their emotions within the last 30 days, reporting both positive and negative feelings such as hope or fear, respectively. The survey also assessed how they managed their emotions, focusing on cognitive reappraisal and suppression as two primary methods. Dr. Anne-Josee Guimond, co-first author of the study and a postdoctoral researcher in Kubzansky's lab, explained that suppression is often a less effective way of handling emotions and can lead to worse mental and physical health outcomes. Cognitive reappraisal involves reframing one’s situation to pick out a more positive angle.
Three months post-survey, the women were asked to submit stool samples, which were subject to metagenomic sequencing. The researchers compared these microbial analysis results with the survey data about emotions and emotional management to identify connections.
Guimond noted that some bacterial species identified in the analysis had previously been linked to poor health outcomes, such as schizophrenia and cardiovascular diseases. “These links between emotion regulation and the gut microbiome could affect physical health outcomes and explain how emotions influence health,” she said.
The analysis revealed that individuals who suppressed emotions had less microbial diversity in their gut microbiome. Moreover, those who reported happier feelings had lower levels of specific bacteria, such as Firmicutes bacterium CAG 94 and Ruminococcaceae bacterium D16, while those with more negative emotions had higher levels of the same bacteria.
More diverse data needed
Kubzansky expressed intrigue at the consistent similarity of findings in opposite directions for positive and negative emotions, stating that it was "kind of amazing" to observe such results.
The researchers also investigated the microbes' functional pathway activity in the gut, searching for links with emotional states and emotion regulation methods. They discovered that negative emotions were associated with decreased capacity activity in multiple metabolism-related actions.
Although the study has limitations, including its focus on mostly postmenopausal white women and the use of a one-off survey, meaning that no causality could be assigned to the findings. Nevertheless, the results pave the way to further work with additional study populations and deeper, longitudinal data.
Reference: Ke S, Guimond AJ, Tworoger SS, et al. Gut feelings: associations of emotions and emotion regulation with the gut microbiome in women. Psychol Med. 2023:1-10. doi:10.1017/S0033291723000612
This article is a rework of a press release issued by Brigham and Women’s Hospital. Material has been edited for length and content.
