If you’re reading this article, you probably have already figured out that probiotics are good for you, but maybe you’re still trying to figure out how to weigh your options. There are so many facets to consider when selecting a probiotic that it can get overwhelming. One of those factors is choosing a probiotic supplement with a single bacterial strain or one with multiple strains. It’s pretty easy to find articles on both sides of the fence. The companies selling single strain products will tell you that bacteria are inherently competitive and will make each other less effective when packaged together. The companies selling multi-strain products will tell you that it is important to take a variety of strains in order to cover a wide range of possible functions, and single-strain probiotic supplements can create a detrimental dominance of one species. Well, we do advocate taking a variety of strains in order to cover a wide range of benefits, and we do caution against single-strain probiotics due to the possibility of creating a dominant species, so I hate to break it to you, but this blog post isn’t going really going to break that mold…except for the part where we provide science to back up our claims! That’s right. Here at Humarian, the makers of a multi-strain and multi-species probiotic, we dish out opinions AND the research to back them.
Dispelling the Single Strain Probiotic Perspective
Let’s start by dispelling the main counterpoint that most proponents of single-strain probiotics like to throw around, that bacteria are inherently competitive and will try to kill each other. It is absolutely true that some bacteria have inhibitory effects on others considering the effect probiotics have on bad bacterial species, but the idea that all probiotics inhibit all others clashes hard with the simple fact that the human microbiota contains more than 400 different species of bacteria.1 More recent studies have estimated that number closer to 800 or 1000 different species. The human microbiota is inherently diverse. It is naturally a multi-strain, multi-species environment. If all bacteria were constantly trying to kill each other, that number would be very small. Good bacteria seek out and kill pathogenic bacteria. That’s a large part of the reason probiotic bacteria are effective in the first place.
Multiple Probiotic Strains Can Have Synergistic Effects
The truth of the matter is that many bacteria have symbiotic relationships with each other and actually boost functions in complementary species. Here’s a simple example in which the adhesion properties of B. lactis were more than doubled when coupled with either L. rhamnosus or L. bulgaricus.2 The results of this study suggest that combinations of probiotic strains can have synergistic effects. And frankly, even in cases where certain probiotics have a somewhat inhibitory effect on each other, they are still probably more beneficial than a single strain. One testimonial page for a single-strain probiotic product that I came across was using a study to back up their claim that multi-strain probiotics are bad because they inhibit each other. The writer of that article must not have read very far into the study because just two sentences later, the abstract states that despite evidence that probiotic species can inhibit each other, a probiotic mixture is more effective at inhibiting pathogens than its component species.3 So even in cases where probiotics have some inhibitory effects on each other, multi-strain probiotics are still more effective at dealing with pathogens than single-strain probiotic supplements. The most important point is that multi-strain mixtures are simply more effective at providing tangible benefits than single-strain probiotic supplements when assembled in synergistic manners. One such study demonstrates that multi-species and multi-strain probiotics were superior to single-strain probiotics in several areas, such as alleviating antibiotic-associated diarrhea in children, protecting against S. typhimurium infection in mice, and dealing with E. coli in lambs.4 It has also been shown that multi-strain probiotics show greater efficacy than single-strain probiotics that are components of the mixtures themselves.5 As usual, research is ongoing in the area of single vs. multi-strain probiotics, but early evidence look to lean heavily in favor of multi-strain. The human microbiota is inherently diverse, so it makes sense that we would want to continue to promote that. If you want to check out Humarian’s own multi-strain, multi-species probiotic, visit humarian.com today!1Gerritsen, J., Smidt, H., Rijkers, G.T. et al. Intestinal microbiota in human health and disease: the impact of probiotics. Genes Nutr 6, 209–240 (2011). https://doi.org/10.1007/s12263-011-0229-7
2Ouwehand, A. C., Isolauri, E., Kirjavainen, P. V., Tölkko, S., & Salminen, S. J. (2000). The mucus binding of Bifidobacterium lactis Bb12 is enhanced in the presence of Lactobacillus GG and Lact. delbrueckii subsp. bulgaricus. Letters in applied microbiology, 30(1), 10–13. https://doi.org/10.1046/j.1472-765x.2000.00590.x
3Chapman, C. M., Gibson, G. R., & Rowland, I. (2012). In vitro evaluation of single- and multi-strain probiotics: Inter-species inhibition between probiotic strains, and inhibition of pathogens. Anaerobe, 18(4), 405–413. https://doi.org/10.1016/j.anaerobe.2012.05.004
4Timmerman, H. M., Koning, C. J., Mulder, L., Rombouts, F. M., & Beynen, A. C. (2004). Monostrain, multistrain and multispecies probiotics--A comparison of functionality and efficacy. International journal of food microbiology, 96(3), 219–233. https://doi.org/10.1016/j.ijfoodmicro.2004.05.012
5Chapman, C. M., Gibson, G. R., & Rowland, I. (2011). Health benefits of probiotics: are mixtures more effective than single strains?. European journal of nutrition, 50(1), 1–17. https://doi.org/10.1007/s00394-010-0166-z