The discovery could lead to yogurts and other probiotic foods that increase longevity.

"In people over the age of 100, an enrichment in a distinct set of gut microbes generate unique bile acids," says lead author Professor Kenya Honda of Keio University in a statement per South West News Service. "They might inhibit the growth of pathogens."

The complex fluids are vital in ridding the body of fat and waste. They also control cholesterol.

"The community of microbes in our gut changes as we age," Prof. Honda adds.

Fighting off superbugs that shorten lives

In healthy individuals, the trillions of microbes that live in our intestines become increasingly distinctive.

"Centenarians are less susceptible to age-related chronic diseases and infection than are elderly individuals below the age of 100," the microbiologist explains. "It is thought the composition of their gut microbiota may be associated with extreme longevity, but the mechanisms have been unclear."