Jan. 30, 2023 -- Gut microbiome appears to play a big role in regulating body temperature, both in long-term health and during life-threatening medical situations such as sepsis, according to a study from the University of Michigan.

The research team looked at data from patients hospitalized with sepsis as well as mouse experiments to determine the connection between the gut microbiome – all the microorganisms living in our digestive systems – and health outcomes, said a news release from the university. 

Researchers examined rectal swabs from 116 patients admitted to the hospital and found that variation in gut bacteria correlated with patient’s temperature changes while they were in the hospital. Specifically, they found that gut bacteria from the Firmicutes phylum was often associated to increased fever. 

"We know that temperature response is important in sepsis because it strongly predicts who lives and who dies," university microbiologist and immunologist Robert Dickson said in the news release. "But we don't know what drives this variation and whether it can be modified to help patients."

The findings were confirmed under controlled experiments with mice.

Gut microbiome may also be the reason human body temperatures have dropped in the last 150 years, the release said.

"While we certainly haven’t proven that changes in the microbiome explain the drop in human body temperature, we think it is a reasonable hypothesis,” said Kale Bongers, MD, lead author of the study. “Human genetics haven’t meaningfully changed in the last 150 years, but changes in diet, hygiene, and antibiotics have had profound effects on our gut bacteria.”

The study published in the American Journal of Respiratory and Critical Care Medicine concluded: “The gut microbiome is a key modulator of body temperature variation both in health and critical illness, and is thus a major, understudied target for modulating physiologic heterogeneity in sepsis.”

Show Sources

University of Michigan: “Gut Bugs Control the Body’s Thermostat”


American Journal of Respiratory and Critical Care Medicine: “The Gut Microbiome Modulates Body Temperature Both in Sepsis and Health”

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