New research has suggested that people that reach the age of 100 or more, centenarians, have a microbiome that could be shielding them from severe infections that are difficult to treat or chronic diseases that tend to crop up as people get older. The microbiomes of 160 Japanese centenarians were compared to microbiomes of two other groups of individuals: 85- to 90-year-old people and 21- to 55-year-old people. The centenarians were found to have higher levels of bacterial species in the colon that generate secondary bile acids than the other groups. Research has suggested that secondary bile acids can protect against pathogens and help regulate immune system responses.   

The researchers next tested how secondary bile acids affect antibiotic-resistant bacteria that cause severe diarrhea and gut inflammation. They found one molecule, called isoalloLCA had strong inhibitory effects on these infections causing disease in humans and animals (clostridioides difficile). 

Feeding mice infected with C. difficile diets supplemented with isoalloLCA similarly suppressed levels of the pathogen. The team also found that isoalloLCA potently inhibited the growth of or killed many other gram positive pathogens, suggesting that isoalloLCA may help the body maintain the delicate equilibrium of microbial communities in a healthy gut.

Sources:  Broad Institute of MIT and Harvard, Nature