Live to be 100? Fermented Foods, Healthy Aging and the Microbiome

Well, I just learned something new.  Did you know that, “Over a century ago, Elie Metchnikoff theorized that health could be enhanced and senility delayed by manipulating the intestinal microbiome with host-friendly bacteria found in yogurt”?^[1]  I had absolutely no idea that healthy aging had been linked to the microbiome and probiotics that long ago!  I have mentioned before on this blog, that the first I ever heard of the concept of probiotics was decades ago, watching the old Dannon yogurt commercials showing unbelieavably spry-looking centenarians in countries like Georgia, who credited their longevity to their yogurt consumption.

Dr. Metchnikoff’s contentions have continually proven correct and today, a quick review of a new paper that I read about on Gut Microbiota for Health.^[2]  Dr. Metchnikoff was not only the first to recognize the relationship of the bacterial microbiome to brain health; he also “…predicted the existence of bacterial translocation and anticipated theories linking chronic inflammation with the pathogenesis of atherosclerosis and other disorders of the aged.”  But wait, there’s more!  He also laid down the scientific justification for fecal microbiota transplant! What a visionary!  By the way, it was obviously his work that gave Dannon the idea for that commercial:  “In contemplating questions related to senility, Metchnikoff’s attention was drawn to the residents of Eastern Europe, in particular those of the Balkan States and Russia, among whom there existed an unusually large number of centenarians.”  It struck him that these people lived a simple, healthy life: plenty of fresh air, exercise, peace and quiet, no alcohol…and lots and lots of fermented foods.

Multiple recent studies show that the gut microbiota in those who live to extreme old age are different from other elderly people.  Starting at age 60-65, “…gut microbiota diversity generally begins to decrease, while enrichment of previously non-dominant bacteria (e.g., potentially pro-inflammatory bacterial groups) and a drop in the number of Bifidobacteria strains occur.”  This is not a benign issue:  these bacterial changes have been linked now to frailty and health.  And surprising to exactly no one, diet is probably the most significant factor in determining the state of the microbiome as we age.

Another study in Japan done on people with an average age of 107, found that these individuals who lived to extreme old age, “…have a distinct gut microbiome that is enriched in microorganisms involved in generating unique and previously unknown bile acids—compounds in bile that aid in fat digestion—that have antimicrobial properties, in particular against Clostridioides difficile, which causes severe diarrhea and colitis.”

However, no study has yet proven definitively that gut bacteria is the direct reason for prolonging life.  A recent animal study shows that giving aging mice a fecal transplant with stool from young mice reverses cognitive decline and reverses brain and body-wide inflammation. Even more remarkable, “The transplantation of the young mice’s gut microbiota also reversed age-related enlargement in microglia cell body size. These cells are the brain’s resident immune cells, which are shaped by the gut microbiome and have been involved in one of the mechanisms that underlie aging.”

While thus far, the relationship between aging and the microbiome is not absolutely proven in humans, what has become clear, is that “…taking care of your gut microbiome is important for a healthy brain and immune system from cradle to grave.”  The good news is that because lifestyle and diet are by far, the most important factors, you have at least some measure of control over the aging of your biome, and thus, inflammaging.  Do as Dr. M did:  “The specific regimen recommended by Metchnikoff for suppressing putrefactive colonic bacteria consisted of daily doses of probiotics in the form of “soured milk (i.e., yogurt) prepared by a group of lactic bacteria, or of pure cultures of the Bulgarian bacillus (Lactobacillus bulgaricus).”

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^[1] Mackowiak, PA. Recycling Metchnikoff: probiotics, the intestinal microbiome and the quest for long life.  Frontiers in Public Health. 2013. |https://doi.org/10.3389/fpubh.2013.00052

^[2]   https://www.gutmicrobiotaforhealth.com/is-healthy-aging-and-increased-longevity-connected-to-the-gut-microbiome/