How does your microbiome affect your health and longevity?
Your microbiome is associated with how healthily you age, but whether you can deliberately steer it to live longer has not yet been proven. A fibre-rich diet and physical activity are currently the most well-supported ways to positively influence your gut flora.
People who live to an exceptionally old age have a strikingly different gut flora than younger people. In people aged 105 and older, certain groups of bacteria, including Akkermansia and Bifidobacterium, are more prevalent than in younger age groups. At the same time, as we age, the presence of common, protective bacterial families gradually declines, while less common and sometimes harmful species take their place. These are associations from observational research, not evidence that these bacteria are the cause of a long life.
A large study of more than 9,000 participants showed that healthy people in their eighties and beyond who had an increasingly personal and unique microbiome composition survived better over a four-year period. People who retained a poorly varied microbiome at an advanced age that closely resembled the average had lower survival rates. This finding is also observational: the association may be mediated by healthy lifestyle habits, health status, or other factors.
The gut flora also influences the immune system and inflammation in the body. Disruptions in the gut flora during ageing likely contribute to two negative processes: a blunting of the immune system and a smouldering chronic inflammation that quietly fuels disease in the background. Through metabolic products produced by bacteria, such as TMAO and short-chain fatty acids, the gut flora also influences the risk of cardiovascular disease. This mechanism is biologically plausible, but randomised trials in humans are largely lacking.
Animal research has shown that a gut microbiota transplant from healthy mice to mice with accelerated ageing extended lifespan and improved health. Even the administration of the bacterium Akkermansia muciniphila alone had an effect. Whether this also works in humans is unknown. Clinical applications in humans are still at a very early stage and safety has not been sufficiently studied to recommend this as an anti-ageing strategy.
Probiotics and prebiotics are sometimes suggested as a way to address this, but the evidence for them in humans falls short. There are still too few data on which bacterial strains make a precise difference for which person to give targeted advice. If you want to positively influence your gut flora, lifestyle measures that have broader support, such as a fibre-rich diet and physical activity, are for now the most concrete tools available.
All claims are based on observational and mechanistic studies or reviews; randomised trials for interventions in humans are lacking. Animal research (mouse models) does provide causal indications but has not yet been translated into proven human applications.
Can your microbiome reveal how old you are biologically?
Your microbiome does send signals about how you are ageing, but a reliable clinical test to measure your biological age with it does not yet exist. It certainly makes sense to take your gut health seriously, even if it is still too early to know how best to do so in order to slow ageing.
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.
Does your gut microbiome affect how well you sleep?
Your gut microbiome influences your sleep through substances it sends to your brain, and poor sleep in turn disrupts your gut bacteria. A fibre-rich diet and a regular sleep and eating schedule are the best concrete steps you can take right now.
Is fermented food good for your health and your microbiome?
Fermented food, and kefir and yoghurt in particular, likely has beneficial effects on gut flora and several health markers, but the evidence in humans is still limited and does not apply equally to every product.
Can you permanently change your gut microbiome through diet?
Diet does indeed change your gut microbiome, but lasting change requires lasting adjustment of your dietary pattern; a temporary diet has only a temporary effect.
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.