Life Extension and the Microbiome: Can we Manipulate the Microbiome to Help us Live Longer?

Answer: Possibly. We already determined in a previous article that it is possible to selectively feed certain bacterial populations. The question now remains whether there are certain longevity-associated bacteria.

A recent Italian study compared the microbiomes of semi-supercentenarians (aged 105+), centenarians (age 99-104), young elderly (65-75 years old), and young adults (aged 22-48).

The study points out that in all age groups, the microbiome is dominated by just three families: Bacteroidaceae, Lachnospiraceae, and Ruminoccaceae, but their cumulative relative abundance appears to decrease as we age (cumulatively 77.8% in young adults vs. 57.7% in semi-supercentenarians). The study, however, was not a longitudinal study that tracked the subjects over years. Thus, while not discussed by the investigators, I question the conclusion that the abundances necessarily change as we age. It is also quite possible that a lower overall composition of Bacteroidaceae, Lachnospiraceae, and Ruminoccaceae is associated with longer life, and that the younger subjects sampled lack the longevity bacteria (since we don’t know whether the younger subjects will become centenarians or semi-supercentenarians). Indeed, given that life expectancy in Italy is 83.2 years, it is probable that most of the younger subjects will not live to see 100, and therefore, do not provide information on the bacterial abundances of those that will become centenarians.

The Italian study found that the abundance of the genera Coprococcus, Roseburia, and Faecalibacterium (belonging to the aforementioned Lachnospiraceae and Ruminococcaceae families) is negatively associated with age (i.e., there are less of these genera as we get older). The trend for decreases in Coprococcus and Faecalibacterium with longevity is also reported in Chinese centenarians. Curiously, Roseburia was significantly increased in the Chinese centenarians, as opposed to the Italian centenarians, indicating that there is not a specific formula to life extension, or perhaps that Roseburia is a non-factor.

The Italian study further states that the genera Akkermansia, Bifidobacterium, and Christensenellaceae are enriched in extremely old people. Akkermansia, as we have discussed in another blog post, is strongly associated with high production of Urolithin A and mitophagy. Bifidobacterium is a “good bacteria” frequently sold as a probiotic. At this time, I don’t know much about Christensenellaceae, but hope to learn more in the future.

The Chinese study, however, found that Akkermansia was “significantly less” in centenarians at the genus level, although it not clear whether significantly less is in comparison to other genus in the same age group, or in comparison to younger people. If it is “significantly less” relative to other genera in the same age group, that is fine, as we already know that Akkermansia is a smaller sub-set of the overall population. The question is not whether Akkermansia dominates the microbiome, but instead, whether its small abundance is helpful or harmful.

Furthermore, despite the occurrences of certain bacterial patterns, it is unclear whether those bacterial patterns improve longevity or whether they are merely representative of age (i.e., closer to death). Meaning, would elderly populations benefit from having a distribution closer to that of a younger person, OR, would younger populations benefit from having a distribution closer to that of a centenarian? We just don’t know at this time because these kinds of longevity studies are difficult to perform. Furthermore, it is unclear whether the centenarians were already born with this bacterial distribution, or whether they developed it as they got older. All in all, it appears that this study gives us more questions than it does answers.

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