Here is a surprising (to me) outcome of a mouse gut biome study that increases longevity and lowers inflammation in aged mice. Surprising because the presence of gram-negative bacteria, which normally increase inflammation because they constantly shed their highly inflammatory Lipopolysaccharide (LPS) outer coating, actually lowers inflammation in the intestinal lining of the old mice in this study: https://www.fightaging.org/archives/2022/01/rejuvenating-the-gut-microbiome-of-aged-mice-in-various-ways/

The bacteria, Akkermansia muciniphila (AK), along with three rejuvenation procedures including co-housing of young and old mice, injection of young serum into old mice, and parabiosis between young and old mice, all increased the population of butyrate-producing microbes increased lifespan and rejuvenation of muscle in these tests. The bottom line here is that while the three rejuvenation strategies increased the population of AK, which then increased the population of butyrate-producing bacteria, so did oral administration of AK itself. The proof of rejuvenation was the restoration of muscle health and the remission of sarcopenia in the old mice – a very convincing outcome, brought about by the increase in butyrate-producing organisms. Could it be that butyrate levels in the gut are the bottom line cause of rejuvenation and longevity? If so, why not just eat mor butter (a good source of the fatty acid butyrate – especially in grass fed livestock). Or, look for a probiotic with significant amounts of AK to come to market sometime soon.