Probiotics are high on the list of things I’ve written the most about here on Darwinian-Medicine.com. The principle reason why I’ve devoted so much time and space to the probiotic industry and its promotion and sale of supplements and nutritional products containing live bacteria is that I’m of the belief that the probiotic enterprise is based on a fallacy.
As I see it, the majority of probiotic supplements are useless. I’m completely on board with the idea that a lot of people could benefit from bringing new microbes into their intestines; however, I very much question the notion that it’s prudent and healthy to consistently “bombard” one’s gut with industrially-manufactured products that contain the types of organisms that are currently classified as probiotics.
My experience with probiotics
All of the hype surrounding the human microbiome and the importance of “good bacteria” for maintaining health and vitality has created a situation in which a lot of people unquestioningly use probiotics, irrespective of whether they feel they’re helping or not. I was once one of these people, which is a major reason why I feel so strongly about the whole probiotic thing.
Back in the day, I went through a number of different probiotic supplements in an attempt to enhance my gut health. I was continually let down by the results I was getting (If anything, the supplements made me feel worse), but I stayed on the probiotic-heavy route nonetheless, as I’d been led to believe from reading about probiotics online and listening to probiotic manufacturers that it’s unequivocally beneficial to maintain a steady infusion of carefully selected and isolated bacterial strains into one’s gut.
It wasn’t until I started thinking about the issue from an evolutionary and biological point of view that I realised that I’d been led astray. I then proceeded to ditch the erroneous and simplistic beliefs that had been imprinted in me, as well as the probiotic formulas that had been ‘pushed’ on me.
Current implementations of the probiotic concept fly in the face of evolutionary logic
Many health and fitness aficionados are of the belief that it’s a prudent practise to include probiotic-enhanced milk or one or more probiotic pills in one’s breakfast every morning. This belief is fueled by companies that have made big business selling drinks and pills containing ‘good bacteria’. Such companies need to keep the public hungry for probiotics in order to generate revenue, which helps explain why they commonly claim that it’s beneficial to take in huge numbers of a couple of isolated and encapsulated microbial strains every day.
This notion has no evolutionary support.
Humans co-evolved with a diverse mix of bacteria, fungi, and other small life forms. Throughout our evolution we were routinely exposed to a variety of complex microbial communities found in water, soil, and other parts of the natural environment. Our ancestors certainly didn’t start the day by supplying their guts with billions of cells of a specific variant of Bifidobacterium bifidum, Lactobacillus rhamnosus, or any other so-called probiotic. This is highly relevant to the discussion about probiotics, as natural selection acts so as to bring about organismal adaptation to environmental conditions.
Unfortunately, the aforementioned evolutionary insights were overlooked when the current version of the probiotic concept was created.
The fallacies of modern probiotic research
One doesn’t have to look far and wide to come across so-called science-based articles and statements extolling the virtues of probiotics. What’s typically left out of such praises is the fact that the vast majority of experimental studies that have looked into the health effects of probiotic consumption are of a short duration and focus almost exclusively on the short-term ‘benefits’ of probiotic supplementation, while largely neglecting potential risks and long-term effects.
I’m particularly concerned about the fact that most studies don’t have a follow-up period or look into whether or not the intervention has any lasting microbiota-related effects. The studies I’ve seen that have included these examinations have generally found that things return to ‘normal’ shortly after the intervention is over, which indicates that the relevant exposures haven’t had much of a lasting effect.
I very much question the practise of assuming that it’s beneficial to use probiotics on the basis that probiotics have acute immunomodulatory and pathogen-suppressing effects. It’s not the least bit surprising that an infusion of immunostimulatory lactic acid bacteria into the guts of people who harbor a dysfunctional microbiota and immune system elicit some apparently positive effects. That’s exactly what one would expect to happen, given the definition and nature of probiotics. The fact that probiotics have such acute effects doesn’t necessarily mean that probiotic supplementation is beneficial in the context of microbiome restoration and maintenance. It merely highlights the fact that probiotics have certain powerful effects on the human organism.
The question I ask myself is: Is it good to stimulate one’s gut and immune system in such an artificial way? I’m not the only one who’s raised this question. One of the world’s most experienced and renowned microbiome researchers, Dr. Tore Midtvedt, as well as some of his colleagues, have as well. They’ve highlighted the fact that probiotics may suppress certain commensal gut bacteria and destabilize the gut ecosystem, for example via their production of bacteriocins (1).
Probiotics can certainly be useful In some medical settings; however, I very much question the notion that the average Joe and Jen would benefit from routinely using probiotic supplements. As I see it, the stereotypical probiotic is analogous to a crutch. It can provide acute support and functionality to a frail structure, but it won’t repair the structure. Actually, it may undermine any potential recovery processes, as the continuous ‘probiotic aid’ could keep the structure from becoming fully functional on its own.
There’s great, unrealized potential in the probiotic concept
So far, you may have gotten the impression that I’m opposed to pretty much everything that has to do with probiotics. That’s not actually the case. I’m very skeptical of most of the probiotic supplements that are on the market today, as well as how they are generally utilized; however, I do think there’s great potential in the probiotic concept.
I strongly believe that one of the key measures we need to take in order to bring down the high rates of inflammation-related health problems in modern societies is to reorganize the relationship between humans and microbes; however, I very much question the notion that it’s a step in the right direction to isolate and encapsulate certain milk-loving microbes and proceed to tell people that they should bring billions of such bugs into their guts every day. Such advice clearly conflicts with Darwinian wisdom, as well as what we know to be true about what’s required to produce and maintain stable and healthy ecosystems in general.
As I see it, a much better approach is to examine human-microbe relations in an evolutionary and ecological light and proceed to use the insights gleaned from such an investigation to develop therapies and strategies pertaining to the construction of a healthy microbiota. Among other things, such insights can help us develop supplements or drugs containing viable microorganisms (‘probiotics’) that may prove a lot more useful than the formulations that are currently available to consumers.
Such products would have to contain a different mix of bugs than the generic Lactobacilli-based supplements that are available on the market today and have a more lasting impact on the gut. (Certain companies are already in the process of developing such products, which are sometimes referred to as microbiome modulators or biota therapeutics, as opposed to ‘probiotics’) Additionally, I think we should get away from thinking that it’s advisable to use probiotics for long periods of time.
I think such a second generation of microbiota-targeting products could prove useful. With that said, there’s an open question whether such therapies will deliver much beyond what can already be achieved via fecal microbiota transplantation, consumption of fermented vegetables, and other existing microbiota restoration strategies.
The countless probiotic formulations that have entered the marketplace over the most recent decades generally have little in common with the natural sources of microbes to which the human biology has become accustomed throughout its evolution. The use of these novel products inevitably has a variety of acute physiological effects, including immune and gut-related impacts, which helps explain why probiotics have been shown to curb or ameliorate symptoms of several health problems and diseases; however, it generally does little or nothing in terms of actually augmenting or enhancing the ecosystem in question. On the contrary, it may destabilize the system by altering its dynamics and suppressing the growth of probiotic-susceptible organisms. This is particularly true if the probiotic product in question is a highly potent one (i.e., one that contains very high concentrations of bacteria) and supplementation continues for a long period of time (i.e., many weeks or months). A reformulation of the probiotic concept is required to expose and realise its full potential.