Distinct Gut Bacterial Communities are Associated with Personality Traits: Study


About 45% of the U.S. population experiences elevated and persistent fatigue, a common, costly, and poorly understood problem.

It has been estimated that fatigue costs employers over $136 billion per year in lost productivity.

However, these estimates do not account for fatigue-related driving and other accidents, poor medical performance, school absences, and declines in school performance and negative health outcomes.

Fatigue is underreported in medical care and linked to many diseases and disorders.

Despite fatigue’s high financial and social costs, it is a poorly understood problem despite there being over 250 different instruments and no consensus about how best to measure fatigue.

One challenge for fatigue researchers is articulating the conceptual relationship between fatigue and energy.

“Our findings reinforce many of the public health concepts related to nutrition and health,” said Dr. Matthew Lee Smith, a researcher in the Department of Environmental and Occupational Health and the Center for Population Health and Aging at Texas A&M University.

“Gut microbiome may be influencing the way you are, not just the way you are today,” he added.

“The findings are more suggestive than definitive, but they have contributed to our understanding of what gut health can do and how it makes people feel.”

In the study, Dr. Smith and colleagues studied the correlation between mental energy (ME), mental fatigue (MF), physical energy (PE), physical fatigue (PF) and the gut microbiome.

“Twenty subjects who were 31 years old, physically active, and not obese participated,” they said.

Bacteroidetes (45%), the most prominent bacterial phyla, was only negatively correlated with PF.

The second most predominant phyla, Firmicutes (43%), had members that correlated with each trait.

However, the bacteria Anaerostipes was positively correlated with ME and negatively with MF and PF, respectively.

Diet influences the gut microbiota composition, and only one food group, processed meat, was correlated with the four moods: positively with MF and PF and negatively with ME and PE. Only the Firmicutes genus Holdemania was correlated with processed meat.

“What you eat determines the bacteria and the microbiome in your gut,” said Dr. Ali Boolani, a researcher in the Department of Physical Therapy and the Department of Biology at Clarkson University.

“With this study, we have made an exploratory link between a person’s microbiome and their mood.”

“We know that energy and fatigue can be influenced by so many things like what you eat, your physical activity, your sleep, your chronic conditions or the medications you take for these conditions,” Dr. Smith said.

“Understanding how nutrition and malnutrition are linked to fatigue and energy is important because falls, chronic fatigue and low-energy can diminish the health and quality of life for older adults living with chronic conditions.”

“I think part of the fun here is looking at some of these relationships and being able to better see this interplay and how what you eat can influence these things.”

The study appears in the journal Nutrients.


Ali Boolani et al. 2022. Trait Energy and Fatigue May Be Connected to Gut Bacteria among Young Physically Active Adults: An Exploratory Study. Nutrients 14 (3): 466; doi: 10.3390/nu14030466