One way to define aging is to view it as the expression of the cumulative effects of microbiome insults.
Aging takes a toll on the human microbiome. As the years pass, we are more likely, for instance, to be exposed to stress, prescription drugs, dietary ingredients such as emulsifying agents or synthetic sweeteners, develop diminished levels of stomach acid, and other factors that cause healthy bacterial species to diminish in number or disappear and allow unhealthy species to proliferate. And, in many older adults, unhealthy species ascend up the ileum, jejunum, duodenum, and stomach–small intestinal bacterial overgrowth, SIBO–increasing the burden of unhealthy microbes, as well as export bacterial and fungal breakdown products into the bloodstream, the process labeled “endotoxemia” that explains how intestinal microbes are able to export their effects throughout the body.
It could therefore mean that a reorganization of the intestinal microbiome might yield benefits in stalling, even reversing, some of the phenomena of aging. Our L. reuteri experience–just one microbe that has been lost by most modern people–for instance, that can smooth skin and reduce wrinkles, accelerate healing, restore youthful muscle mass and strength, preserve bone density, demonstrates that such age-reversing effects are indeed possible. Can we go even further than the benefits of this one microbe?
The gut microbiome changes observed with aging include:
- Increased Proteobacteria—These are species like Klebsiella and E. coli that produce endotoxin. The greater the populations of Proteobacteria, the greater the degree of endotoxemia. Even modest increases can yield marked changes in health and, likely, aging.
- Increased Streptococcal species—While the majority of microbes that overpopulate in dysbiosis and SIBO are so-called Gram-negative (describing how they appear with a Gram stain process for visualization under a microscope) Proteobacteria, Gram-positive species such as Streptococcus can also proliferate.
- Decreased Akkermansia—Akkermansia is one of several keystone species that yield considerable metabolic advantage. There is evidence that healthier older adults harbor 3-fold greater Akkermansia species compared to unhealthy older adults.
- Decreased intestinal alkaline phosphatase—This crucial enzyme disables bacterial endotoxin and keeps it from entering the bloodstream. As we age, we lose alkaline phosphatase. Conversely, restoration of alkaline phosphatase has not only been shown in experimental models to reduce brain changes of Alzheimer’s dementia, but to also improve metabolic markers like blood sugar and substantially increase lifespan.
- Increased endotoxemia—It has been known for a number of years that aging is accompanied by a chronic, low level of inflammation that worsens as the years pass. Preliminary evidence even suggests that endotoxemia can trigger the pathological brain markers of dementia, as well as many metabolic markers that deteriorate with age (e.g., blood sugar, insulin sensitivity, triglycerides. blood pressure). As the degree of dysbiosis worsens, the more inflammatory endotoxins are exported from the GI tract to other parts of the body, the sooner end-effects such as beta amyloid plaque in the brain, insulin resistance, and other consequences develop.
- Decreased nutrient production—Healthy species are able to produce a number of nutrients such as vitamins B1, B2, B3, B6, B9, B12, and K2 from various dietary factors. As healthy microbes are replaced by Proteobacteria and others that lack the capacity to produce such nutrients, dysbiotic humans develop nutrient deficiencies that may contribute to the phenomena of aging.
Efforts to restore a more youthful microbiome has potential to reduce many of the phenomena of aging, especially:
- Immunosenescence—i.e., the deterioration of immune function with aging. Much of the body’s immune system resides in the gastrointestinal tract and has bidirectional interaction with resident microbes. It is already well-established that specific microbes have potential to increase immune responsiveness. Loss of immune competence includes immunosurveillance, the immune process that prevents cancers. Lactobacillus casei Shirota is one microbial species/strain that I have discussed that enhances the immune response, in this case to respiratory viruses.
- Inflammaging—the increase in inflammation with aging marked by increases in measures such as IL 1-beta, IL-6, C-reactive protein, and TNF-alpha.
- Hormonal senescence—Numerous hormones decline with age such as progesterone, testosterone, oxytocin, and growth hormone. We now know that restoration of the microbial species, L. reuteri, lost by most people, restores oxytocin and probably testosterone and growth hormone. (We have studies planned to better document these phenomena.)
There are factors that account for the phenomena of aging beyond the microbiome and intestinal barriers, of course. But addressing these issues holds potential to exert substantial effects in slowing or reversing many of these phenomena.
By following the Wheat Belly lifestyle, you have taken a big first step in countering the effects of aging, especially by avoiding the gliadin protein that increases intestinal permeability and endotoxemia. But we can go further by adopting such practices as supplementing EPA+DHA from fish oil to activate intestinal alkaline phosphatase; including oleic acid oils in the diet such as olive oil that provoke a bloom in Akkermansia and also reduces endotoxemia; increasing intake of prebiotic fibers that are metabolized by microbes to butyrate that strengthens the intestinal barrier to endotoxins. I shall discuss these issues and more in coming Wheat Belly Blog posts.