The most common probiotics hail from the genera Lactobacillus and Bifidobacterium. But today researchers have been identifying new genera of bacteria isolated from the healthy human gut that may become the probiotic of the future. (See here for a previous blog on this topic.) Although many proposed ‘next generation’ probiotics have not yet been tested in humans, recently a study was published in Nature Medicine evaluating the safety of Akkermansia muciniphila ATCC BAA-835, for potential use as a probiotic for cardiometabolic effects.
This was a randomized, double-blind, placebo-controlled pilot study of 40 healthy subjects (32 completed the trial). The trial administered daily for 3 months live A. mucinophila (1010 cfu/d), pasteurized (heat killed) A. mucinophila, or an inert placebo (glycerol). The objective of the study was to determine if these substances were safe. Too few subjects were in the study to expect any clinical benefits to be measured, but still some improvements were observed, specifically with improved blood lipids and insulin resistance. Interestingly, though, these benefits were observed only in the group taking the heat-killed Akkermansia, not for the subjects taking the live bacteria.
The study concluded that the tested strain and dose of A. mucinophila, either live or heat-killed, was well tolerated. Further, the study hinted that the heat-killed strain may mediate some cardiometabolic benefits. Of course, such a preparation of dead cells could not be considered a ‘probiotic’, even if a subsequent study confirmed health benefits. (See here for a previous blog on this topic.) Indeed, the word ‘probiotic’ was not used once in this report. But reports are emerging that suggest that dead microbes may confer some physiological benefits. This is an emerging field in need of research to clarify the extent of benefit conferred by, and mechanisms of actions employed by, dead cells as they influence human health.