Classify this as a speculative piece, some musings on the role of small intestinal bacterial overgrowth, SIBO, and small intestinal fungal overgrowth, SIFO, on the phenomena of aging. I am asking the questions:
Could many of the phenomena of aging be a manifestation of SIBO and SIFO? And, if so, could the phenomena of aging be slowed or reversed by managing these situations?
The evidence is incomplete to make firm associations, but consider:
- Up to a third of the elderly have hypochlorhydria due to atrophic gastritis, i.e., low or absent stomach acid due to either H. pylori or gliadin-protein induced autoimmune gastritis. Lack of stomach acid is a powerful setup for SIBO. Others have taken stomach acid-suppressing drugs for years that also set people up for SIBO, not to mention the fact that much acid reflux is yet another manifestation of SIBO. In other words, SIBO is rampant among the elderly.
- If we accept that blood levels of homocysteine can serve as a marker for dysbiosis due to decreased capacity for microbial production of vitamins B6, B12, and folate, should we therefore see higher homocysteine levels in the elderly? Here is a study of Chinese centenarians with median homocysteine levels of 23.8 micro mol/L—exceptionally high compared to most younger people who have levels typically around 8 micro mol/L. Of course, higher homocysteine levels could also be due to impaired B12 or folate intake or absorption, so the association is uncertain.
- As people age, more and more become lactose intolerant, a marker for SIBO. In a small Australian study, for instance, of 10 elderly people with lactose intolerance, 90% had SIBO (by lactulose H2 breath testing); eradication of SIBO reversed lactose intolerance in all initially SIBO-positive participants. Likewise, in an Italian study, lactose intolerance was associated with SIBO; eradication of SIBO resulted in most people being freed from lactose (as well as fructose and sorbitol) intolerance.
- It is not uncommon for the elderly to die of sepsis, i.e., blood borne infection that often has no identifiable source. By a wide margin, the most common microorganisms recovered from the blood of these people? Enterobacteriaceae, the microorganisms of SIBO.
- While brain tissue of young people is devoid of fungi, the brains of elderly people are riddled with fungal species, while people with dementia light up like the lights in a city when stained for fungus. People with fungal infections typically also experience other fungal phenomena, such as fungal skin, toenail, and sinus infections, but where are the fungal infections originating? My bet is the gastrointestinal tract, i.e., SIFO.
Couple this with the phenomena of immunosenescence, ie., impairment of the immune system that people develop with aging that results in increased risk for infections. Immunosenescence occurs in the gastrointestinal tract, the seat of much of the body’s immune system, also—could this allow SIBO/SIFO to take on more ominous meaning in this setting?
Even more interesting, the oxytocin-boosting effects of our L. reuteri yogurt hugely stimulates the immune system, including increased expression of immune-protective CD4+ lymphocytes and reversal of age-related thymus involution, in addition to this microoganism’s capacity to colonize the upper gastrointestinal tract and produce bacteriocins antibiotics effective again Enterobacteriaceae–the species of SIBO.
This is just a speculation, one that will need to be explored and validated. In the meantime, there is nothing lost and potentially much to gain. For a more extended discussion, including the steps you can take on your own to take advantage of the potential anti-aging effects of SIBO/SIFO management, take a look at the Undoctored Advanced Topic on this issue in the Undoctored Inner Circle.