Two of the questions we hear all the time are…”How can taking a probiotic really make a difference when there are, literally, trillions of bacteria in your gut.” And “Can taking a probiotic really change the composition of good vs bad bacteria in the digestive system?”
Reservations about the effectiveness of probiotics in the context of our overall microbiome have been expressed in the past, but have now received more press after recent Danish research that concluded that probiotics had no effect on fecal microbiota in healthy adults. Several media outlets picked up on the story and have suggested that since probiotic supplements have no measurable effect on fecal microbiota they have no effect on your health overall.
This overly simple interpretation of the research results is wrong. The Danish researchers did not address the question – whether probiotics have a health benefit or not - only if probiotic consumption could cause a significant change in the participants microbiome.
The fact that probiotics do not affect fecal microbial composition, in a statistically significant way, isn’t surprising. There are trillions of bacteria that already inhabit our gut, so the ability of a few billion probiotics to change the bacterial composition of the gut is a little like adding a needle to a haystack and expecting needles to dominate.
Our view: is that there is still a lot to be learned about the benefits of specific bacterial strains and physiological benefits that does not mean probiotics do not provide a benefit at all. Research has also shown that probiotics achieve their health effects via many different mechanisms of action, and not just by materially changing the populations of bacteria in your gut.
This view is also supported by Professor Glenn Gibson (University of Reading) who makes an interesting observation “It puzzles me that we can easily accept that orally ingested pathogens have massive effects at negligible doses, often being completely undetected in feces, but do not foresee the same for probiotics.”
Probiotics are natural products, and are not “one size fits all solutions”, individuals can have different experiences depending on a lot of things. However, probiotics and our gut microbiome are valuable unseen workers protecting us and helping us stay healthy. So just because you do not feel anything, or you don’t notice the same changes as others do, does not mean that nothing positive is happening.