Some people live longer than others – possibly due to a unique combination of bacteria in their intestines, new research shows.

Some people spend small fortunes on antiaging supplements, gadgets, treatments and diets, but others glide effortlessly into a relatively healthy old age, clocking up a century or more on the clock, seemingly all by themselves. What is their secret?

Researchers from the Novo Nordisk Foundation Center for Protein Research at the University of Copenhagen set out to answer this question by studying Japanese centenarians.

Longevity.Technology: The study, which was published in Nature Microbiology, involved 176 healthy Japanese centenarians. Previous studies have demonstrated that the intestinal bacteria of elderly Japanese people produce novel molecules that confer resistance against disease-causing microorganisms, and this finding led the team to investigate whether enhanced protection against infections played a role in their longevity.

The research team discovered the combination of intestinal bacteria and bacterial viruses in the individuals studied is unique [1].

“We are always eager to find out why some people live extremely long lives. Previous research has shown that the intestinal bacteria of old Japanese citizens produce brand new molecules that make them resistant to pathogenic – that is, disease-promoting – microorganisms. And if their intestines are better protected against infection, well, then that is probably one of the things that cause them to live longer than others,” said postdoc Joachim Johansen, who is first author of the new study [2].

In addition, the study revealed that certain viruses that reside in the intestines can exert a positive influence on the composition of the intestinal flora, ultimately contributing to our overall health and well-being.

“Our intestines contain billions of viruses living on and inside bacteria, and they could not care less about human cells; instead, they infect the bacterial cells. And seeing as there are hundreds of different types of bacteria in our intestines, there are also lots of bacterial viruses,” said Associate Professor Simon Rasmussen, last author of the new study [2].

Johansen added that aside from the important, new, protective bacterial viruses, the researchers also found that the intestinal flora of the Japanese centenarians exhibited interesting biological diversity [1].

“We found great biological diversity in both bacteria and bacterial viruses in the centenarians. High microbial diversity is usually associated with a healthy gut microbiome. And we expect people with a healthy gut microbiome to be better protected against aging related diseases,” he added [2].

Understanding the composition of the intestinal flora in centenarians could provide insights into increasing life expectancy in the general population. Using a specially designed algorithm, the researchers successfully mapped the intestinal bacteria and viral populations of the centenarians in the study.

“We want to understand the dynamics of the intestinal flora,” said Rasmussen. “How do the different kinds of bacteria and viruses interact? How can we engineer a microbiome that can help us live healthy, long lives? Are some bacteria better than others? Using the algorithm, we are able to describe the balance between viruses and bacteria [2].”

By deciphering the intricate relationship between viruses and bacteria in Japanese centenarians, the researchers hope to discover the optimal balance for both components. This knowledge could help us understand how we should optimise the bacteria found in the human body in order to protect it against disease.

“We have learned that if a virus pays a bacterium a visit, it may actually strengthen the bacterium,” explained Johansen, adding that the viruses we found in the healthy Japanese centenarians contained extra genes that could boost the bacteria.

“We learned that they were able to boost the transformation of specific molecules in the intestines, which might serve to stabilise the intestinal flora and counteract inflammation [2].”

“If you discover bacteria and viruses that have a positive effect on the human intestinal flora, the obvious next step is to find out whether only some or all of us have them,” said Rasmussen. “If we are able to get these bacteria and their viruses to move in with the people who do not have them, more people could benefit from them [2].”

While further research is needed, the study’s new insights are significant, especially because we can already modify the intestinal flora.

“Intestinal bacteria are a natural part of the human body and of our natural environment. And the crazy thing is that we can actually change the composition of intestinal bacteria. We cannot change the genes – at least not for a long time to come,” said Rassmussen.

“If we know why viruses and intestinal bacteria are a good match, it will be a lot easier for us to change something that actually affects our health [2].”

[1] https://www.nature.com/articles/s41564-023-01370-6
[2] https://healthsciences.ku.dk/newsfaculty-news/2023/05/why-do-some-people-live-to-be-a-100/