(Image courtesy bio.pisceswebdesign.com.)
The evidence is building supporting the idea that there is a species of bacteria called Akkermansia muciniphila that, when present in substantial numbers in the colon, yields powerful effects. Akkermansia is unrelated to most other species that colonize the human intestinal tract (a member of an entirely different phylum, Verrucomicrobia, that includes many soil species). It is also unusual in that it does not feed on dietary prebiotic fibers like most other microbes that inhabit the human intestine, but feeds on the mucous lining (mucin or mucous polysaccharides) of the intestinal tract (mucin- and -phila, or love), while yielding metabolites that support other probiotic species. Although it consumes mucous, it also encourages intestinal mucous production and strengthens the intestinal barriers that reduces potential for inflammation. Akkermansia is believed to be a foundational microbe whose presence encourages the presence of other desirable species and has been associated with greater species diversity, a strong marker for health.
Colonization of the colon with Akkermansia begins with breastfeeding as an infant, as it is present in human milk. Because no longitudinal studies have been performed, it is not entirely clear what happens to Akkermansia over the decades of human aging.
Most of the evidence for the potential benefits of Akkermansia come from experimental animal models but suggests that an abundance of this bacterial species can:
- Prevent weight gain
- Reduce lipopolysaccharide (LPS) entry into the bloodstream. Recall that LPS is a breakdown product of bacteria, especially species that proliferate with dysbiosis or small intestinal bacterial overgrowth (SIBO), and is exceptionally inflammatory in the body, even fatal when occurring at high enough levels.
- Reduce measures of inflammation
- Amplify the immune response and increase likelihood of a successful immune response against cancer cells
- Reduce insulin resistance
Most of the human evidence is observational with associations such as less abundant Akkermansia in people with type 2 diabetes, people who are overweight, people with ulcerative colitis. A recent groundbreaking study examined bowel flora composition of mice in which seizures were provoked; reduction in seizures on a ketogenic diet was found to be due to Akkermansia and Parabacteroides in bowel flora and anti-seizure activity could be mimicked by simply supplementing these bacterial species. Yes: Akkermansia can prevent/reduce seizure activity.
While some people have as much as 4-5% of their total bowel flora occupied by Akkermansia, most have much less, typically 1-2%. There may therefore be metabolic and other advantages in increasing the Akkermansia population. The evidence suggests that, to increase Akkermansia in the gut, you can add some things and you can subtract some things. Among the factors to consider:
Prebiotics–especially inulin/FOS that markedly amplifies Akkermansia growth, up to 100-fold in experimental models.
Polyphenols–These are the red-, purple-, orange-colored vegetables and fruits that, for not entirely clear reasons, encourage Akkermansia growth. Especially potent stimuli include cranberries, grapes, and pomegranate. (Red wine is uncertain: While rich in polyphenols, the ethanol reduces Akkermansia and the net effect–increase or decrease–remains unclear.)
Green tea–The epigallocatechins of green tea, like the polyphenols of veggies and fruit, also encourage Akkermansia.
Grains and sugars–i.e., the components of a high-carb diet. Low-carb diets therefore increase Akkermansia, as with the ketogenic diet. (The arabinoxylan and amylose of grains, however, also stimulate Akkermansia; but, of course, grains come with so much other unhealthy baggage—the presence of these two prebiotic fibers is insufficient to justify their inclusion.)
Excess weight–Weight loss from obese or overweight levels increase Akkermansia.
To be sure, there are still many unanswered questions surrounding this fascinating bacterial species. For instance, are there strains of Akkermansia muciniphila that are preferable with a better profile of benefits, as there are likely at least a dozen different strains? (The strain used in most of the above studies was ATCC BAA-835.) Recall that strain specificity, while often ignored in, say, commercial probiotics, is a crucial detail, as with our L. reuteri yogurt that utilizes the ATCC PTA 6475 and the DSM 17938 strains, the only strains proven to exert the effects we desire.
On a personal note, I looked back at my uBiome analysis from a couple of years ago: zero Akkermansia, a situation I share with about 3-5% of people. This is tough: There is no commercial probiotic to supply this species, nor is there any way to create it out of thin air if you don’t have it. Fecal transplant would do it, of course, but . . . . ewwww. Only if the data mature and justify such an effort. In the meantime, anyone out there in the probiotic research/commercialization community, if you have a means to seed our intestines with Akkermansia, please speak up on the comments in this blog or the Undoctored or Wheat Belly Facebook pages.