Probiotics: Single or Multi-Strain, What’s the deal?

Okay, so you’ve finally been inoculated (pun intended) into a world filled with friendly bacteria and optimal digestive health. After meticulously researching the foods and supplements crawling with the live critters of your choice, now only one question remains:

Should you opt for single-strained or multi-strained probiotics? More importantly, does your choice make any difference in the effectiveness of your probiotic supplementation?

Single-Strains & Multi-Strains: What’s the Difference?

 Simply put, the difference between single-strain and multi-strain probiotic supplements is how many bases you’re willing to cover before completely trusting their function.

Research shows that probiotics with a single strain of bacteria are just as effective as multi-strain versions, so it is really a matter of preference- and a most importantly, of education.

Single Strain Probiotics Are Okay

 The probiotic industry was unfortunately founded on clever marketing strategies that have developed to become what some consider a huge hype. While there are significant studies backing the health benefits probiotics can provide, the unmonitored processing of probiotic products means that manufacturers can (and do) manipulate labels to make their yogurt or tablets more appealing.

When it comes to multi-strain probiotics, manufacturers are using the simplest of consumer beliefs which is “more of a good thing must be better”. Actually, when we’re talking about bacteria, more (and more importantly diversity) means competition.

One of the main obstacles a quality probiotic product must overcome is the corrosive environment of the human digestive tract. This is the main reason you’ll find probiotic yogurts and fermented veggies in the refrigerated isle. Much care has been taken to keep the bacterial strains alive until they reach the digestive tract. Now here’s how multiple strains don’t make sense:

Bacteria compete for survival, this is, after all, the main mechanism by which probiotics overtake the gut microflora- by overpowering existing bacterial strains. The worry with probiotic supplements boasting  “8 Different Strains!” is that those eight different strains are very likely to compete with each other for the right to live in your gut. This defeats the purpose of taking a probiotic in the first place.

How Strain Diversity Can Work

 Diversity in probiotic strains is different and can definitely be used in a constructive manner to improve gut health. The three main species can be divided into the following categories of function:

  1. The Lactobacillus Species

The most common of gut bacterial strains are made up of the Lactobacillus species. These bacteria produce lactase and lactic acid via fermentation of carbohydrates.The main function of the Lactobacillus species is to combat the growth of toxic microorganisms via its production of lactic acid, a substance that also functions as a catalyst for the absorption of calcium, magnesium, and iron.

L. acidophilus, a member of these species, is one of the two primary bacterial strains to look for in a probiotic supplement because of its antimicrobial properties, inhibition of carcinogenic substances, and evidence preventing up to 23 known pathogens.

On the other hand, here are three Lactobacilli strains to look for in multi-strain probiotic supplements. These guys not only get along well with other species, but also improve the overall formula of any probiotic supplement.

L. salivarius: A basic to any probiotic formula, L. salivarius aids in digestive activities by optimizing absorption of vital nutrients and aiding in the disposal of old fecal matter. It also produces a slew of detoxifying enzymes and forms a protective film along the intestinal wall.

L. rhamnosus: A main protagonist in the tumor-fighting arena, L. rhamnosus boosts the body’s immune response by increasing levels of circulating antibodies.

L. plantarum: A strain almost completely extinct from our diets, L. plantarum is an essential tool in eliminating pathogenic bacteria. L. plantarum is so effective, that were it to simply colonize its area of preference within the gut, it would eradicate colonies of E. coli via basic territorial dominance.

  1. The Bifidobacterium Species

The Bifidobacterium are the second most important bacterial strain to look for in probiotic supplements. They spend their existence lining the walls of the colon where they act as a defense barrier to unwanted microorganisms. Bifidobacterium also produce lactic acid, which in this functional context serves as fuel for the good bacteria lining the large intestine and a toxin for unwanted bacteria.

Studies have shown a marked link between low levels of bifidobacteria and the development of chronic degenerative diseases. Additionally, healthy levels of bifidobacteria in the large intestine can prevent tumors by consuming the enzymes which catalyze their formation in the mammary glands, the liver, and the colon.

  1. The Bacillus Species

Bacillus bacteria are the toughest of the gut microflora, designed to resist the highly acidic environment of our gut. These are the bacteria on the offense side of the battlefield.

Important Note on Probiotic Supplements

 Consuming probiotics via tablet, capsule, or powder supplements carries unique risks such as die-off rate, special storage needs, and the nature of coexistence between the bacterial strains used.

Something to pay attention to when researching probiotic supplements is the wording of the label. For example, most labels will list the amount of live organisms per capsule (or gram, tablet, etc.) “at the time of manufacture”. This is usually there to distract from the actual amount of live organisms, which may be down by billions by the time you actually swallow the capsule.

Also make sure that your probiotics are packaged in the supernatant, or simply put, their own juices. The supernatant is the medium the bacteria were grown in originally; it contains vital byproducts that aid in colonization and development. Bacteria- live bacteria- are already a fragile substance to handle, so uprooting them from the medium they were grown in can increase their die-off rate and effectiveness.


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  1. Hummel, Anja S., et al. “Antibiotic resistances of starter and probiotic strains of lactic acid bacteria.” Applied and environmental microbiology 73.3 (2007): 730-739.
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1 Comment
  1. Reply Mike Harper @Probiotic Strains April 26, 2016 at 3:24 pm

    Lactobacillus Bulgaricus is actually one of the first strains of probiotics that have been studied. Russian Nobel Prize winner, Ilya Mechnikov, first discovered this probiotic in fermented sour milk.

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