Longevity: the Secret May Lie in The Bacteria That Live in The Gut


Longevity: Some people over 100 years of age have a greater number of unique intestinal microbes that inhibit the growth of pathogens in the organ, allowing these individuals to live longer.

This is the conclusion of an article published in late July in the journal Nature that could be another step towards revealing the secret of longevity, sought by generations throughout history.

To assess this likely relationship between enteric microbiota and lifespan, the researchers looked at microorganisms in the intestines of people of different ages. Of the 319 individuals studied, 160 of them were at least 100 years old (107 on average), 112 were between 85 and 89 years old, and 47 people were younger, aged between 21 and 55 years old.

The study suggests the possibility of manipulating a set of bile acids, metabolizing the capabilities of these friendly bacteria for the benefits they are capable of providing to health.

However, speaking to the Live Science website, one of the study’s authors, Kenya Honda, recommends caution, as “we don’t have any data showing the cause and effect relationship between them.”

The human microbiota

In recent years, several studies have been published with strong evidence that a good quality of life is related to intestinal health. These researches demonstrated that some bacterial profiles in the intestine are linked to psychological and psychiatric disorders, both through direct influence on the brain and cardiovascular protection.

Our microbiota, also called intestinal flora, begins soon after the baby is born, with the mother being the primary source of these microorganisms.

Research indicates that colonization of enteric bacteria can begin even before childbirth, inside the uterus. The metabolic profile is influenced by numerous factors.

New research hypotheses

The gut microbiota is the sum of all microorganisms that reside in the human gut. Composed primarily of bacteria, but also including certain fungi, archaea and even viruses, this community of microbes plays an important role in our health as we age. Thus, less bacterial diversity has been associated with frailties in older adults.

Based on this premise, the researchers hypothesized that centuries-old people may have intestinal bacteria that contribute to their good health and, consequently, to their longevity.

The results of the comparative analysis revealed that individuals over 100 years of age have particularly high levels of a secondary bile acid (produced in the liver) called isoallolithocholic acid (isoalloLCA). By identifying which bacteria specifically produced isoalloLCA, they found that they belonged to the Odoribacteraceae family.

But the most important finding was that isoalloLCA has potent antimicrobial properties, which theoretically could inhibit the growth of harmful bacteria in the gut. In an experiment with rats, application of the acid slowed the growth of Clostridium difficile, a bacterium that causes diarrhea and inflammation in the colon. IsoalloLCA also inhibited the growth of antibiotic resistant enterococci.

If these bile acid-producing bacteria are naturally helpful for a healthy gut, then they could be used as probiotics, Honda ponders, to preventively improve human health in younger people. According to the microbiologist, these biological cells proved to be safe for the human body, as they do not secrete toxins or harbor antibiotic-resistant genes.

Although the survey did not collect information about the participants’ diet, exercise habits or medication use, the field of study is promising. Future trials with larger populations may provide more accurate information about the relationship between intestinal bacteria and longevity.


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