Longevity Briefs: Gut Bacteria And Ageing – What We Know

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: The populations of bacteria inhabiting our gut change and become less diverse as we age. More and more evidence is emerging that declining biodiversity in bacterial populations throughout the body (especially the gut) is an important driver of age-related diseases like cancer and diabetes. A recent review revisiting the hallmarks of ageing – the common denominators of the ageing process that provide the most promising targets for treatment – included gut microbiome disruption as one of the 12 hallmarks of ageing. Among all the hallmarks, changes in the gut microbiome are perhaps the easiest to reverse.

What did the researchers do: In this review, the authors give an overview of what we currently know about the gut microbiome, its role in age-related disease, and how we could leverage it to improve human health.

Key takeaway(s) from this research:

• The composition of the gut microbiome is closely linked with ageing, and can be used to predict someone’s age quite accurately.
• Centenarians (people who live past age 100) have more diverse gut microbiomes than much younger people, while frailty is associated with less diversity at a given age.
• Transplanting bacteria from young mice into prematurely ageing mice slows down the pace of ageing.
• There is some evidence that transplanting bacteria from healthy donors can help treat human disease.

It’s clear that declining health of the gut microbiome is associated with human ageing and age-related diseases. However, there are many ways in which someone’s rate of ageing could impact the gut microbiome, rather than the other way around. For example, people with weaker immune systems struggle to suppress populations of harmful bacteria, while poor diet may encourage a loss of biodiversity in the gut. 

Animal studies make it clear that the composition of the gut microbiome can affect the ageing process, at least in some species. For example, transplanting bacteria from healthy young mice can significantly improve the lifespan of prematurely ageing mice. Treatments targeting the microbiome remain relatively unexplored in humans, but there is some tantalising evidence about how such treatments could benefit us. In one of the most remarkable examples, cancer patients were given faecal transplants from other patients who responded well to cancer immunotherapy. These recipients then responded better to immunotherapy than patients who did not receive faecal transplants. 

So, the gut microbiome may hold huge potential for the treatment of age-related diseases. However, when it comes to the current level of human evidence, the gut microbiome may be a little ‘overhyped’. Hopefully, this won’t remain the case for much longer.