Probiotics are a class of supplements based on “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” That definition was agreed upon by the World Health Organization only in 2001.
Old concept, relatively new category
Humans have consumed live microorganisms as part of their food supply almost from the inception of the species. In other words, we’ve been getting microorganisms into our mouths since we’ve had mouths, and the microflora in our gut was there from day one.
But while involuntary ingestion of bacteria has always been part of what we consume, and fermented foods laden with potentially beneficial bacteria have a long history of use, too, focused supplementation with live microorganisms is quite new.
In previous installments in this series, I considered whether two other classes of dietary supplements—herbal supplements and those based on omega-3s—were improving in quality and efficacy. In many important ways, I believe the answer to that question is yes.
These are ingredients that have a history of use for their medicinal properties that stretches back thousands of years in the case of botanicals and more than a century for fish oils, the first form of omega-3s on the market. Bacteria have of course been getting into our mouths since we had mouths, but if we take the advent of the WHO definition as the real foundational event of the commercial category, then probiotics are the youngest of the three.
Probiotics have come a long way in a very short time. The foundational science has been ramping up quickly. The Human Microbiome Project launched only in 2008, and wrapped up in 2013. This project, coordinated by the National Institutes of Health, gave the first comprehensive look at what kinds of microorganisms live within and upon us. A second phase looked at the distribution of microbial species associated with various disease states, such as inflammatory bowel disease and type 2 diabetes. The effort has generated reams of subsequent research.
A good portion of this research has been conducted by suppliers of probiotics themselves. These studies support the targeted benefits associated with named strains of probiotics, including their effect on the immune system as well as on gut health overall. These studies have added significantly to the understanding of the category as a whole.
Exciting new areas of research include looking at the effect of intestinal microflora on cognition and mood states, the so-called gut-brain axis. Early clues were taken from physiology, where it was observed that more serotonin, an important neurotransmitter, was produced and used in the gut than in the brain.
Success brings criticism
Probiotics haven’t excited just researchers. Marketers have latched on to the category in a big way, sending sales soaring. High profile national TV ad campaigns have made this a mainstream category and have even given many otherwise uninformed consumers an inkling of what probiotics can claim to do.
But has all of that research ferment caused some manufacturers to make over sensationalized claims? Of course it has. But the prevalence of well-made probiotics, using named strains with carefully constructed claims in amounts that correspond to published research, has increased as well.
The popularity of the category has brought its detractors. Prominent industry critic Dr Pieter Cohen, MD, of Harvard published a paper just this week that is highly critical of probiotics, saying that the safety of the products is unproven and many claims are unsupported by science. (Dr Cohen hasn’t singled probiotics out for this treatment; he remains unimpressed by the safety data associated with most kinds of supplements.)
The International Probiotics Association responded that there is little evidence of a safety concern for probiotic usage among healthy individuals, while admitting a few tragic outlier cases of probiotic supplementation harming already compromised individuals (such as a seriously ill preemie baby) do exist. And IPA has been developing protocols for what kind of safety data manufacturers should have to bring new probiotic strains to market.
Near term improvements, promise for the future
IPA is close to finalizing manufacturing guidelines for its members. And FDA, with input from IPA and other trade organizations, has changed its stance on the labeling of these products (from milligrams to CFUs), which will give consumers better information for comparing products.
Some aspects of probiotic formulation are still be sorted through, which is characteristic of the newness of the category. Are one-species products the way to go? Or is a suite of different species superior? Do supplements that employ generic genus/species type probiotics provide a reasonable facsimile of a given health benefit at a bargain price point, or is this stuff just junk riding on the scientific coattails of more expensive products? Are huge CFU counts necessary and superior to counts in in low billion range? The jury is still out on these and other questions.
But the combined efforts of stakeholders show the category is uniting around some common themes of manufacturing quality and efficacy data. Despite Dr Cohen’s concerns, the safety record of the category has been good. And new research, especially in the area of personalization using the genetic profiles of individuals, holds great promise.
For example, the authors of a review paper published earlier this month had this to say: “As the impact of probiotic interventions on the gut microbiota are further investigated, it may soon be possible to identify likely responders to a specific probiotic, enabling more successful utilisation in the future.”
So, are probiotics improving as a category? I think the answer is a clear yes. And they offer the potential for big public health wins in the not too distant future that can serve to burnish the reputation of dietary supplements as a whole.