Senescence, Aging…and the Microbiome: Part 2

As I promised last Thursday, I’ll finish talking about the article[i] on aging, the microbiome,  and senescence today.

A quick summary of my last post:  the evidence currently available points to a depletion of the microbiota as we age (from diet (for example, older people – who may have dental issues – may not eat enough fibrous foods, etc.)), use of antibiotics throughout life, stress associated with aging and so forth:  “…these old-age-related clinical issues could clearly contribute to the increased predisposition to various infections and gut-associated diseases by causing alterations in the microbiota of elderly people.”  Also, the build-up of senescent cells (especially cells of the immune system) may also result from microbiome depletion, as the gut bacteria are crucial for normal immune functioning.  “…however, we still do not have a complete understanding of the mechanisms underlying the aging-mediated changes in the gut microbiome configuration, or whether these microbial changes are the cause of consequence of senescence.”

While we wait (hopefully, not too long) for science to provide us an easy way of “spring cleaning” – lowering our levels of senescent cells (see my last post for more on this) – the article provides us some things we can do now…which, as you know, is my favorite thing to write about.

1. Levels of  short-chain fatty acids (SCFAs) has been shown to be lower in the elderly, and is correlated with lower fiber intake and antibiotic treatment. These reduced levels are associated with susceptibility to inflammatory bowel diseases, the development of leaky gut (which in turn, of course, causes systemic inflammation to rise), have a negative impact on insulin sensitivity and more.  Thus, “…dietary or relevant therapeutic interventions (e.g. using fiber-rich diets or indigestible-carbohydrates [prebiotics] that promote SCFAs production through fermentation by gut bacteria) that restore/promote the microbiome in a way that the intestinal organic environment is also restored/promoted in terms of beneficial SCFAs might turn out to be effective for ameliorating the aging-related ailments, particularly those originating in the senescent gut.”
2. Some good news in all this: “…the available evidences on the associations between gut microbiota, nutrition and systemic inflammation suggest that dietary interventions for positively modulating the microbiota composition and diversity could help in promoting the healthier aging and longevity.”
3. Remember that SCFAs are anti-inflammatory. Thus, boosting levels may be “…particularly important for elderly people, because they are already going through immune-senescence and are at increased risk of developing miscellaneous infections and illnesses.”
4. Using prebiotics and probiotics to maintain a healthy bacterial microbiome has been shown to aid in the “…prevention of senescence-related diseases such as C.difficile-associated diarrhea, constipation, and common respiratory and gastrointestinal infections.”
5. Unfortunately, right now (and believe me, no one is sicker of this phrase than me): we simply don’t have enough information to conclude that using probiotics and prebiotics will work in the “…prevention of old-age related illnesses and immune-senescence.”   However, preliminary results do hint at their “…possible potential in improving the gut environment and lowering the incidences of senescent illnesses.”

The article concludes with hope:  “…given the mounting evidence that the gut microbiome plays a fundamental role in numerous aspects of our health and disease, it can be easily envisioned that novel personalized nutritional and therapeutic approaches targeting the intestinal microbiota such as probiotics, prebiotics, nutraceuticals, functional foods, and fecal microbiota transplantation may offer potential  avenues for better health and wellbeing with a particular relevance for our senior comrades.”

Considering that every one of us is getting older by the day, the time to care for you old friends is now.

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[i] Nagpal, R, et. al.  Gut microbiome and aging: physiological and mechanistic insights.  Nutrition and Healthy Aging. 2018;4:267-285.