This article explores growing scientific interest in the gut microbiome and its potential role in healthy ageing. Research on centenarians consistently shows that people who live long, healthy lives tend to have more diverse gut bacteria, which may help reduce inflammation, support resilience, and protect against frailty. While gut diversity naturally declines with age, those who maintain it appear to age better, not just live longer.

The article follows a journalist who undergoes microbiome testing and works with experts to improve his gut health through diet. Findings suggest that significant dietary changes, particularly eating fibre-rich plant foods, fermented foods, healthy fats like olive oil, and minimizing ultra-processed foods, can shift the gut microbiome within weeks. Studies, including animal research, suggest gut bacteria may directly influence ageing processes rather than simply reflect overall health.

Experts caution that gut health is only one piece of the longevity puzzle, alongside genetics, exercise, and lifestyle factors. However, diet may account for up to one-third of how we age, making everyday food choices a meaningful and accessible way to support long-term health.