ageing gut – Research on ageing and the gut microbiome suggests dysbiosis is often linked to inflammation that damages gut immunity over time. While probiotics have shown benefits for some age-related conditions, evidence that they—along with prebiotics or postbiotics—can
The problem begins quietly, the kind you might blame on a busy week or a slightly off meal—until it doesn’t go away.
I’ve spent years writing about biomedical science. and I have an annoying talent for developing the symptoms of whatever I’m investigating. Chronic sinusitis left me with a persistent snuffle. A hearing-loss article made me certain I was going deaf. When the topic was snoring, I snored louder and longer than ever. Usually, the symptoms vanish once the draft is done.
Not this time. About a year ago, I wrote about chronic constipation. My diet hasn’t changed. I drink plenty of water and exercise regularly. So why am I still here—stuck with a problem that, for many people as they age, can be one sign of something deeper.
In later life. the gut microbiome often shifts in ways that may contribute to dysbiosis. a disruption of the ecosystem inside the large intestine. Throughout much of adulthood it tends to stay remarkably stable. but as people enter older age it often changes—usually for the worse. One possible result is constipation. But that’s the least of the worries, because the gut microbiome doesn’t just sit there. It interacts with the immune system and, through a chain reaction, can influence inflammation across the body.
Dysbiosis is difficult to define precisely because each person’s microbiome is highly individualized. shaped over decades by diet. environment and medical history. As an approximation, it’s a shift away from cooperative, beneficial microbial species toward more pathogenic ones. Many studies have found that ageing is typically associated with a loss of overall microbial biodiversity. especially among “friendly” bacteria that ferment dietary fibre to produce anti-inflammatory molecules. Their places are taken by more aggressive groups such as Enterobacteriaceae—an umbrella that includes many harmless species but also E. coli, Salmonella and Shigella.
A commonly cited cause is ageing of immune cells in the lining of the large intestine. These immune cells spend life cultivating friendly gut microbes and keeping “nasties” at bay. Eventually, they run out of steam. The bad actors gradually take over.
From there comes a vicious cycle. Pathological microbes breach the once-impermeable gut wall and enter the bloodstream. That triggers an immune response and fuels chronic and widespread low-level inflammation. This phenomenon has a name: “inflammaging.” And the inflammation doesn’t stay local. It further damages the gut’s immune cells. amplifying dysbiosis. while also being linked to a wide range of diseases of old age—from the brain and liver to kidneys. muscle. bone. fat and lungs.
Still, not everyone follows the same arc. Some people who live to an especially advanced age seem to have a surprisingly spry gut microbiome. In a widely discussed case. researchers in Spain analysed the blood. saliva and faeces of 116-year-old María Branyas Morera. the world’s oldest living person at the time. She died in August 2024 at 117 years and 168 days. The researchers reported that she had three longevity “superpowers”: an abundance of genes associated with extended lifespan. incredibly efficient lipid metabolism. and—crucially—a gut microbiome characteristic of a much younger person.
Her microbiome was particularly rich in a genus called Bifidobacterium. These bacteria produce anti-inflammatory molecules, and they typically decline in abundance with age. Morera wasn’t treated as a single-person miracle. Studies of large numbers of centenarians have consistently found that they have a youthful gut microbiome.
So the question becomes urgent: if dysbiosis is something to avoid, what can people actually do?
One idea is to find out what’s happening inside. Having a gut microbiome analysed is one option. but in the UK it isn’t available through the National Health Service. Many private companies offer at-home testing kits instead. The problem is that the results may not be reliable enough to guide decisions. A recent analysis of seven such kits. carried out by a team led by Stephanie Servetas at the US National Institute of Standards and Technology in Gaithersburg. Maryland. found they were of limited use because results vary widely between providers. The team concluded that the diagnostic capabilities of these tests remain largely underdeveloped.
Diet is where most people turn next—and where the evidence is often easier to translate into daily life. Andrea Ticinesi at the Microbiome Research Hub at the University of Parma in Italy described what people eat as “the main environmental factor shaping gut microbiome composition.” A year-long clinical trial backed that idea. It found that a Mediterranean style diet—loaded with vegetables. legumes. fruits and nuts. cereals and a moderately high amount of fish. plus olive oil—boosts levels of beneficial bacteria linked with reduced inflammation. lower frailty and better cognitive performance.
My own diet already resembles that pattern, but the tempting follow-up is whether supplements can push the microbiome further.
Probiotics are often marketed for exactly this purpose. They are supplements containing live bacteria, mainly Bifidobacteria and Lactobacilli. Clinical trials have shown that probiotics can alleviate some conditions commonly associated with ageing—specifically muscle wasting and mild cognitive impairment—through changes to the gut microbiome.
But the story doesn’t end with reassurance. The evidence does not suggest that probiotics make any inroads into inflammaging. For prebiotics and postbiotics, the picture is even slimmer. Prebiotics are supplements designed to promote the growth of beneficial bacteria. Postbiotics are mixtures of dead bacteria or their component parts. Yet the evidence for both prebiotics and postbiotics is lacking.
Sleep and exercise also show up in this research landscape as levers that can improve the gut microbiome.
If there’s a single takeaway that feels both practical and grounded in the facts, it’s this: the gut microbiome may be able to be nudged in ways that affect certain age-related symptoms—but reversing inflammaging appears to be a much harder target.
And perhaps that’s why people keep returning to the example of Morera, who attributed part of her extraordinary longevity to eating three portions of natural, unsweetened yoghurt a day. The researchers who examined her said this probably kept her gut replenished with Bifidobacteria.
I rarely eat yoghurt. Now I’m thinking about changing that—at least for a while. Three portions a day is her number, not mine. But if the gut’s microbiome is where young-like patterns might be preserved. it’s hard to ignore a simple habit that seems to align with the bacteria linked to anti-inflammatory effects.
gut microbiome dysbiosis inflammaging probiotics prebiotics postbiotics Bifidobacterium Lactobacilli Mediterranean diet