How to choose a probiotic

The world of commercial probiotics is evolving rapidly as the science of the microbiome continues to unfold. Unfortunately, the current crop of commercial probiotics provide limited benefits, as they are generally concocted in a haphazard fashion. Most current commercial probiotics are a slap-dash collection of microbes, each of which is believed to be beneficial or at least not harmful.They provide limited benefits that include helping suppress the proliferation (but not usually eradicating) unhealthy species such as Klebsiella and Staphylococcus, encourage production of intestinal mucus and strengthening the intestinal immune response, yielding healthy metabolites like butyrate, and produce nutrients such as B vitamins. But a carefully crafted probiotic could accomplish a lot more.

First of all, let’s make clear that among the most important strategies you can follow in re-achieving a healthy microbiome and overall health is the inclusion of plentiful fermented foods: kimchi, kombucha, kefir, yogurts, fermented vegetables, fermented meats, etc. While the species in the fermented foods themselves typically do not take up long-term residence in the GI tract, by an uncertain mechanism the microbes originating with fermented foods somehow encourage restoration of healthier bacterial species. I would regard this as taking priority over taking a commercial probiotic in their current form.

Nonetheless, there are several features that are worth considering in choosing a probiotic:

• Strains should be specified—Lactobacillus rhamnosus GG strain, for instance, helps stop the diarrhea that results after taking an antibiotic, but most other strains of L rhamnosus do not. Yet the strain is not mentioned on most commercial probiotics that include this species and you won’t know whether it works or not (it likely does not). (There are also situations in which strains do not matter; having made yogurt with 8 different strains of L. reuteri, for example, I have experienced all the effects I experienced with the original Gastrus strains—the provocation of oxytocin may be a characteristic shared by most or all strains within this species. I am planning a small experimental trial to explore this question.)
• Include species that colonize the upper gastrointestinal tract (not just colon)–As this is where small intestinal bacterial overgrowth, SIBO, occurs that, I believe, is epidemic among Americans. Shockingly, there’s a trend to encapsulate probiotics in double-capsules or other devices to delay release into the colon, not the small intestine—big mistake.
• Synergistic effects on intestinal mucus and the intestinal barrier—Combinations of microbial species and non-microbial components can provide very powerful ways to reduce intestinal permeability (leakiness”) and reduce endotoxemia and thereby body-wide inflammation and insulin resistance. For example, including probiotics that cause proliferation of Akkermansia muciniphila and Faecalibacterium prausnitzii, coupled with green tea catechins that cross-like mucin proteins in intestinal mucus is a powerful combination.
• Include keystone species—i.e., species that support other species
• Include collections of species and strains that “collaborate” or have “guild” effects—that amplify benefits. This is the theme, for instance, for my friends Dr. Raul Cano and Martha Carlin’s BiotiQuest line of probiotics that includes Sugar Shift that has helped many followers of the program reduce blood sugars further.
• Choose species that produce bacteriocins (natural antibiotics) that kill undesirable species
• Produce nutrients such as B vitamins and vitamin K2
• Produce neurologically active metabolites such as acetylcholine, dopamine, GABA, and serotonin. Combined with suppression of microbial species that yield lipopolysaccharide (LPS) endotoxin, this may be the key pathway, by the way, to finally developing a genuinely effective way to manage or reverse depression.

No current commercial probiotic meets all these criteria. In the defense of probiotic manufacturers, there are also essential species that pose challenges such as dying upon exposure to oxygen. My current favored probiotic, while still imperfect, is Synbiotic 365. In my new Super Gut book, I go into greater detail on how to manage choosing a probiotic, in addition to various maneuvers you can put to work to save a ton of money on probiotics by making them yourself.

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