The key to healthy ageing could be the composition of bacteria in the intestine as researchers have found that people who live longer than usual have gut bacteria similar to 30-year-olds.

The researchers studied the gut bacteria in a cohort of more than 1,000 Chinese individuals in a variety of age-ranges from three to over 100 years old who were self-selected to be extremely healthy with no known health issues and no family history of disease. The study, published in the journal mSphere, showed that the overall microbiota composition of the healthy elderly group was similar to that of people decades younger, and that the gut microbiota differed little between individuals from the ages of 30 to over 100.

"The main conclusion is that if you are ridiculously healthy and 90 years old, your gut microbiota is not that different from a healthy 30-year-old in the same population," said Greg Gloor, Professor at University of Western Ontario in Canada and principal investigator of the study.Whether this is cause or effect is unknown, but the study authors pointed out that it is the diversity of the gut microbiota that remained the same through their study group."This demonstrates that maintaining diversity of your gut as you age is a biomarker of healthy ageing, just like low-cholesterol is a biomarker of a healthy circulatory system," Gloor said. 

The researchers suggest that resetting an elderly microbiota to that of a 30-year-old might help promote health."By studying healthy people, we hope to know what we are striving for when people get sick," Gregor Reid, Professor at Western University's Schulich School of Medicine & Dentistry.