The Gut Microbiome and Longevity: Do Our Microbes Affect Our Lifespan?
The quantity and diversity of bacteria in our gut microbiomes vary widely from person to person. Each microbial makeup begins its unique journey starting at birth, continually altered along the way by dietary and lifestyle habits, environmental conditions, age, medications and more. It can even change based on which people—or animals—you share your home with.
Despite these person-to-person differences, each individual microbiome tends to stay relatively stable in terms of the species it houses for most of its life. However, upon reaching mid-to-late adulthood, the bacteria in our guts start to shift—and these microbial changes can reflect not only variations in health outcomes but also differences in how long we live.
How Does the Microbiome Change With Age?
Within the intricate folds of the five-foot-long tube in our guts known as the large intestine lives upwards of 100 trillion bacteria. Hosting approximately 4,000 different species, our large intestine, also known as the colon, is prime real estate for microbes—both good and bad. Referred to as the gut microbiome, this collection of bacteria that resides in our intestinal tracts can be imagined as a lush rainforest—just as a rainforest requires a diversity of plants and animals to flourish and remain in balance, our microbiome also needs a wide variety of bacterial species to thrive.
When we’re younger, most healthy people carry microbiomes heavy in Bacteroides—one of the “core bacteria” humans have in common. But as we age, healthy older adults will begin to have more unique bacterial signatures that diverge from the core Bacteroides species. And this uniqueness is important, as the semi-supercentenarians (people who live to be 105 years or older) show much higher levels of bacterial diversity.
Conversely, a lack of microbial uniqueness with age has been associated with increased frailty and physiological decline in older adults. Other research has found that healthy “oldest-old” adults—those aged 90-plus—have increased levels of Akkermansia, which is associated with better metabolic health.
Although we now know much more about the microbiome than years past, it’s still relatively unknown when these age-related changes to the microbiome start to occur and what impact it has—especially on lifespan. Let’s take a closer look at what some of the recent research on gut bacteria and longevity shows.
Gut Microbes and Extreme Longevity: Recent Research
In one study, researchers looked at the microbiomes of over 9,000 adults aged 18 to 101, providing microbiome- and longevity-related data from the largest group of older adults to date.
After analyzing microbial and clinical markers, the researchers found that healthy older adults started to see a shift in their microbiomes between ages 40 and 50, with the most significant change being a reduction in Bacteroides and an increase in more unique bacterial species. However, it doesn’t stop at age 50—the microbiome continues to become more diverse with each passing decade in healthy adults.
Notably, this depletion of Bacteroides with increased unique bacterial species correlated with increased lifespan. In a smaller sample of community-dwelling older adults (i.e., not living in a nursing home or hospital), the research team found that low microbial uniqueness was significantly linked to an increased risk of dying from any cause, with an even stronger association found in those over age 85.
However, this microbial uniqueness and its associated longevity boost only applied to healthy individuals in this study. Older adults who were deemed “unhealthy” had less diverse microbial makeups and no increase in lifespan, suggesting that a unique microbiome not only reflects a longer life but also contributes to it.
In a study in Italy, researchers compared the microbiomes of semi-supercentenarians—people aged 105–109 years—to the microbiomes of young adults, young elderly adults (aged 65-75) and centenarians (aged 99-104). People with extreme longevity (the 105-plus crowd) had significantly different microbial ecosystems than the other groups, including a greater abundance of the health-promoting Akkermansia, Bifidobacterium, and Christensenellaceae.
While some research has shown that adding probiotics like Akkermansia muciniphila to the diets of mice extends their lifespan, we don’t yet know if supplementing with probiotics containing these healthy bacteria would have the same longevity-boosting effects in humans. However, there are ways to improve overall microbiome health, which could naturally shift your microbes to more diverse and beneficial ones.
How to Master Your Microbiome
Although both gut microbiomes and extreme longevity may have a genetic component, there is plenty you can do at any age to maximize your microbiome health, including:
- Eat foods naturally containing probiotics, like fermented vegetables, sauerkraut, kimchi, yogurt and kefir.
- Consume foods high in prebiotics, which are fibrous compounds that the probiotics can feed on to stay alive in the gut. Prebiotic-rich foods include onions, garlic, apples, leeks and less-ripe bananas.
- Take a high-quality probiotic supplement that contains at least 1 billion CFU (colony-forming units) of healthy bacteria per capsule. Multi-strain probiotics are typically recommended for general gut health, while higher amounts of single-strain bacteria can target specific health concerns.
- Limit added sugar and refined carbohydrates, which do not contain the fiber your gut microbes need to survive. In addition, excess sugar intake negatively impacts your gut microbial ecosystem by decreasing bacterial diversity.
- Exercise. Regular physical activity has been shown to enhance the number of beneficial microbial species and enrich bacterial diversity.
To join the ranks of supercentenarians living to 110 and beyond, don’t forget to pay attention to the trillions of microorganisms we host in our guts. After all, it’s not just “you are what you eat,” but rather, “you are what your microbes eat.”
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