Can your gut microbiome influence how long you live?
There are clear indications that the composition of your gut microbiome is associated with how long and how healthily you age, but whether modifying your microbiome extends your life has not yet been demonstrated in humans.
People who reach 100 or older have a gut microbiome that differs from that of younger older adults. Bacteria such as Akkermansia and Bifidobacterium are remarkably prevalent in centenarians, whereas the microbiome of ordinary older adults tends to lack them. This is an association, not a proven cause: we do not know whether that distinctive microbiome is the reason they lived so long, or a consequence of their lifestyle and genes.
The strongest human evidence comes from a large study of more than 9,000 people aged 80 and above. Those who had a more personally distinctive gut microbiome at an advanced age survived better over the following four years. People whose microbiome still closely resembled that of a young adult, with high levels of Bacteroides bacteria, fared worse. This is strikingly consistent, but it is still an association. No one has definitively demonstrated cause and effect here.
Animal research does show that the gut microbiome can be causally involved. Aged mice that received a gut transplant from healthy mice lived longer and stayed healthier. Even transplanting a single bacterium, Akkermansia muciniphila, already had an effect. Whether this works the same way in healthy humans has not yet been tested in people.
There is also a clue as to why a healthy gut microbiome might be advantageous in old age: the gut bacteria of centenarians produce distinctive bile acids that strongly inhibit dangerous, antibiotic-resistant bacteria in the laboratory. This could help explain why people who live to a very old age are relatively resistant to infections. Whether this actually saves lives in practice remains uncertain.
Influencing your microbiome through diet or supplements has been studied in older adults, but the effects are modest. Probiotics and prebiotics can reduce respiratory tract infections and strengthen vaccine responses. A proven effect on lifespan itself has not been established.
This answer is based on multiple human studies, including a large study of more than 9,000 older adults, and on animal research involving gut transplants. The human studies show associations but cannot prove cause and effect. The animal research demonstrates causality, but has not yet been extended to humans. The researchers themselves emphasise that the direction of the association remains unclear: is the distinctive microbiome a cause or a consequence of healthy ageing?
Can your gut microbiome influence inflammation in your body?
Your gut microbiome can influence inflammatory processes throughout your body via the gut wall. Eating more fibre and exercising regularly are the most well-supported ways to influence this favourably.
Can your gut microbiome influence your risk of heart disease?
Your gut microbiome influences your heart health through metabolic by-products that can promote arterial hardening, high blood pressure and blood clots. The association is plausible, but how best to modify the gut microbiome to protect your heart has not yet been sufficiently proven: always discuss major interventions with your doctor.
Can your gut microbiome affect your cholesterol?
Your gut microbiome influences your cholesterol through bile acid conversion and the fermentation of fibres. Eating more fibre is the most concrete and safe step to take; supplements such as berberine are not yet sufficiently substantiated for daily use.
Does my gut microbiome change as I get older, and does it matter?
Your gut microbiome certainly changes as you get older, but whether that is harmful depends strongly on which direction that change goes. What you eat has a major influence on this, so that is a concrete area to pay attention to.
Can your gut microbiome affect your memory and concentration?
Your gut microbiome can influence your memory and concentration through several routes, but most of the evidence still comes from animal and laboratory research. What you can concretely do right now is support your gut health through diet, as direct supplementation or probiotics for cognition have not yet been sufficiently proven in humans.
Can your gut microbiome control your appetite and hunger?
Yes, your gut microbiome can influence your hunger and eating behaviour via a direct connection to your brain. Eating more fibre is the best thing you can do right now to support that route.