People have long given up the search for The fountain of youtha mythical spring that can reverse aging. But for some researchers, the hunt isn’t over – it’s just moved to another location. These modern Ponce de Leóns investigate whether gut microbes hold the secret to aging well.
The gut microbiome refers to the vast collection of microscopic organisms – bacteria, fungi and viruses – that largely reside in the large intestine. These microbes aid in digestion and produce molecules such as affect your physiology and psychology. The composition of the microbiome is influenced by a combination of factorsincluding genetics, diet, environment, medications and age.
You are only as old as your gut microbes
People are most familiar with external signs of aging, such as wrinkles and graying hairbut there are also microscopic changes taking place deep inside. The gut microbes of older people tend to be less diverse, with more bacteria that promote inflammation and other characteristics of aging. Changes in the microbiome across age are so consistent that algorithms can reliably predict a person’s age based on their microbiome composition.
There are exceptions to this rule. Older adults and supercentenarians who age well have a gut microbiome that more similar to younger people. These findings support the idea that maintaining a youthful microbiome promotes healthy aging and longevity.
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To confirm that the microbes of youth influence aging, researchers use a technique called transplantation of faecal microbiota. This procedure involves wiping out a person’s current gut microbiome and replacing it with microbes harvested from a donor’s stool. Transplantation of microbiota from a young mouse to an older mouse reverses age-related inflammation in the gut, brain and eyes. Conversely, transplanting microbiota from an old mouse to a young one accelerates these aging parameters. Other studies suggest that microbiota from young mice change the metabolism in ways that reduce inflammation that accelerates aging.
The evidence that aging is linked to the microbiome is compelling. However fecal transplantation is not without risk and is approved only as a last resort treat seriously C. difficile infections. These shortcomings have prompted researchers to search for safer and more refined ways to cultivate an age-friendly microbiome.
Diet and exercise can slow down aging
Correct diet and exercise have long been linked to better aging and longevity. One way these lifestyle habits can be beneficial is through their impact on intestinal microbes.
What people eat – or don’t eat – has a demonstrable effect on their gut microbiomes. The standard american dietenriched with ultra-processed food that is high in sugar, fat and salt and low in nutrients and fibre, timber microbiome diversity within days. Moving from a non-Western country to the United States is also associated with loss of gut microbiome diversitypartly due to dietary changes.
Lack of fiber is an important reason the microbiome adopts a configuration associated with poor aging. Studies in roundworm, mouse and rats found that fiber supplementation improved overall health and extended lifespan by 20% to 35%. A 2025 study found that increasing the amount of fiber in your diet is linked to as much as one 37% greater likelihood of healthy aging in women.
Fiber functions as prebioticsan indigestible food component that nourishes the microbiome. Intestinal bacteria process fiber into compounds such as short-chain fatty acids which promotes better aging by improving metabolic, brain and immune function while reducing chronic inflammation. Good sources of prebiotics includes most fruits and vegetables, whole grains, legumes, nuts and seeds.
Certain foods, such as yogurt and kefir, or dietary supplements contain probiotics – live microbes that can benefit the gut microbiome. Research on probiotic foods and supplements is mixed, complicated by the variation in bacterial species and dosage in these products. The health benefits that different types of probiotics can provide are still under study.
Physical activity is also linked to a youthful microbiome. Regular exercise can reshape the microbiome of older adults to resemble those seen in younger adults. One study found that when people aged 50 to 75 underwent 24 weeks of cardiovascular and resistance training, microbiomes were populated by healthier bacteria and their blood had elevated levels of pro-aging short-chain fatty acids.
Treatments to manipulate the microbiome
Making healthy lifestyle changes is a non-invasive way to cultivate a youthful microbiome that can slow aging. Scientists are also exploring treatments to tailor the gut microbiome for better health outcomes.
One option could be postbiotics, non-living but active compounds which probiotic microbes produce. For example, mouse studies have found that short-chain fatty acid supplementation can be improved age-related heart and lung problems. Correspondingly, older mice are given heat-killed bacteria from a human infant so reduced metabolic dysfunction and inflammation, as well as improved cognitive function.
The microbiome can also be modified with drugs, in particular antibiotic. A low-dose oral antibiotic can trigger intestinal bacteria to release factors that can promote good health and aging by, for example, strengthening the intestinal barrier or reducing inflammation. One such antibiotic, cephaloridine, extends the lifespan of roundworms and mice by triggering gut bacteria to create cholanic acid, an anti-aging compound.
Bacteriophages, or phagesoffers yet another potential way to manipulate the microbiome for health. Subjects are highly selective viruses which infect and kill specific bacterial species. Fager has been used to treat serious infections from bacteria that are resistant to antibiotics. Given that subjects can alter the gut microbiome of miceresearchers are studying whether they can be used for eliminate gut bacteria associated with unhealthy aging.
Aging is a natural process that can bring many rewards. Cultivating a healthy microbiome can help people enjoy their golden years more fully.
This edited article has been republished from The conversation under a Creative Commons license. Read original article.
