It’s no secret that with aging comes inflammation—and the subsequent heightened risk of a whole bunch of health conditions. There’s even a word for the low-grade, chronic inflammation that develops as we get on in years: “inflammaging.”
Still, there’s no set amount of inflammation that comes with age. Some people will develop more of it, and more disease, than others.
“People of the same chronological age can have very different inflammatory and metabolic profiles. This suggests that chronological age alone does not capture the biological processes underlying healthy or unhealthy aging,” says Carsten Eriksen, Ph.D., researcher in the Department of Biotechnology and Biomedicine at the Technical University of Denmark and the Center for Molecular Prediction of Inflammatory Bowel Disease (PREDICT) at Aalborg University’s Department of Clinical Medicine.
Eriksen and his co-authors set out to investigate whether the composition of gut microbiota—all the different bugs living in your digestive tract—could help explain these disparities. They discovered something fascinating. Their findings, published in Nature Communications, suggest that a person’s gut microbiota can better predict their risk for future disease and inflammation than age—making the microbiome a “potentially modifiable determinant” of age-related disease development.
So, what does this mean for you? Ahead, more on the study and its takeaways.
Meet the expert: Carsten Eriksen, Ph.D., researcher in the department of biotechnology and biomedicine at the Technical University of Denmark and the Center for Molecular Prediction of Inflammatory Bowel Disease (PREDICT) at Aalborg University’s Department of Clinical Medicine.
What did the study find?
The researchers enrolled 1,199 participants, aged 20-72. They took blood samples, which they used to measure inflammatory cytokines—proteins released by immune cells, which control inflammation—and fecal samples to analyze gut microbiota. Additional indicators of health, including VO2 max, blood pressure, heart rate, body fat percentage, and levels of cholesterol, creatine, calcium, and sodium, were also measured. The scientists then tracked the participants for up to nine years through national health registers to monitor for new diagnoses.
After they crunched the numbers, the researchers found that gut microbiota composition “was more strongly associated with most of the inflammatory and physiological measures we examined compared to chronological age,” Eriksen says. For 29 of 30 cytokines and 16 of 19 biochemical or physiological variables, microbiota composition explained variance better than age. “These findings suggest that gut microbiota composition is an important correlate of inflammatory and health trajectories across adulthood,” Eriksen says.
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Additionally, people with Bacteroides 2, or B2 enterotype—a certain classification of gut microbiota associated with lower diversity and abundance of bacteria—were more likely to have higher inflammation markers, higher triglycerides, lower HDL cholesterol, and lower VO2 max. They also had an increased risk of subsequent disease diagnosis.
“These differences were particularly apparent in younger adults, giving the profile an inflammaging-like appearance earlier in adulthood,” Eriksen says. “In contrast, individuals with a so-called Richness profile, who had a high gut bacterial diversity, generally had lower levels of inflammation and lower overall disease risk.”
Why might the composition of your gut microbiota predict inflammation and disease?
While it’s not clear exactly what’s behind this, Eriksen has a few theories. “Some bacteria associated with the B2 profile may interact with the intestinal barrier, microbial metabolites, and innate immune pathways in ways that promote systemic immune activation,” he says. “The low diversity often means that several of the beneficial bacteria are gone or at least depleted, which we hypothesize could weaken the intestinal barrier and tolerance and, in turn, increase the risk of adverse immune reactions.”
However, Eriksen warns against overinterpreting the data. “We observed associations between a microbial community pattern and host inflammatory physiology—not a single bacterium acting in isolation,” he says. It’s also important to remember that enterotypes aren’t “discrete biological categories,” just useful classifications; bacteria associated with the B2 enterotype are also found in other enterotypes, but usually in different quantities.
What’s the takeaway?
Eriksen cautions that the study wasn’t designed to prove that gut microbiota composition caused inflammation or disease—or to shed light on how individuals might stave off inflammaging. “The study is observational, so it does not establish that the microbiota causes inflammation or disease,” he says.
More studies are needed, particularly longitudinal ones, where researchers follow up the same people over an extended amount of time, and interventional ones, where scientists actively apply a treatment to analyze the effects. These can help determine cause and effect, as well as whether these patterns can be modified to improve health, he says.
However, working toward a better-balanced gut microbiome is never a bad thing. There are a few proven strategies for supporting gut microbiota, such as adhering to a gut-friendly diet, getting enough sleep, and exercising regularly. Eating a variety of plant-based foods is great for your gut, too. “People can support general health through behaviors such as eating a varied, fiber-rich diet containing vegetables, fruit, legumes, whole grains, nuts and seeds,” Eriksen says.
Other healthy gut-promoting strategies include exercising regularly; maintaining a healthy body composition; avoiding smoking; and moderating alcohol intake, Eriksen says. “A healthy lifestyle may help support a resilient gut microbial ecosystem and reduce several established drivers of chronic inflammation.”
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