The properties of probiotic strains are vastly dissimilar, resulting in a large variety of probiotic products with distinct documented effect or no documented effects. Many products only specify the species contained, and not the strain. For example, a product may be labelled Lactobacillus rhamnosus, but whether the strain is Lactobacillus rhamnosus, LGG®, the very different Lactobacillus rhamnosus, GR-1®, or any other Lactobacillus rhamnosus strain, is not known, and so neither is the documented potential health benefit. Further, clinically observed effects are associated with a specific potency and the probiotic product must be consumed live and at this potency.
A higher number of CFUs does not necessarily equal a superior effect. Instead, choosing a probiotic product at an appropriate CFU level, which is clinically associated with the desired effect is the best option. For example, Bifidobacterium, BB-12® has been associated with a increased defecation frequency in adults with constipation just as well at a dose of 1 billion CFU/day as with 10 billion CFU/day,1 whilst a beneficial effect of Lactobacillus, LGG® at a level of 10 billion CFU has been observed in several studies,2, 3 and therefore supplementation with Lactobacillus, LGG® at 10 billion CFU/day is often recommended, due to its association with reduced duration of gastroenteritis in infants and children.4
The number of strains in a probiotic product does not determine its functionality; the particular strain, the specific combination, and the clinical evidence is what should be considered, as many available multi-strain products lack clinical support for either the single strains they contain, or the combination of strains used. For example, Lactobacillus, LGG® as a single-strain product has been associated with beneficial immune system support,5, 6, 7 Lactobacillus rhamnosus, GR-1® and Lactobacillus reuteri, RC-14® in combination have been shown to help support urogenital health,8, 9, 10, 11, 12 and the combination of Bifidobacteria, BB-12®, Bifidobacteria infantis Bb-02 and Streptococcus thermophilus, TH-4® has been associated with reduced necrotizing enterocolitis in very preterm infants.13
Since fermented foods are developed by using existing microbes or adding a live culture to a food, they contain live microbes. Often, however, a fermented food will go through further processing such as pasteurization, baking and filtering, thus killing the live microbes. Even if a fermented food does not go through one of these processes, it is still not necessarily termed a probiotic, as it may not have documented health benefits, or a specific potency associated with its consumption.
Yogurts can be a good source of probiotics but not all yogurts contain probiotics. All yogurts contain starter cultures (such as Streptococcus thermophilus and Lactobacillus bulgaricus), but only some yogurts include probiotic bacteria. Several yogurts have probiotic bacteria added together with the fermenting culture in order to ensure that the right amount of specific bacteria is present in the yogurt at the end of shelf life. Probiotic bacteria such as Bifidobacteria, BB-12®, Lactobacillus acidophilus, LA-5®, Lactobacillus rhamnosus, LGG® or Lactobacillus paracasei, L. CASEI 431® can be delivered in adequate amounts in yogurt which then qualifies the yogurt as a source of probiotic bacteria.
Probiotics can help restore the microbiota when negatively affected by antibiotic use. Probiotcs may also be able to help address potential side effects of antibiotics - Lactobacillus rhamnosus, LGG® has been associated with reducing the frequency of antibiotic-associated diarrhea,14, 15 whilst combining antibiotic treatment with Lactobacillus rhamnosus, GR-1® and Lactobacillus reuteri RC-14® has been associated with improved result with respect to bacterial vaginosis, compared to treatment with antibiotics alone.8, 16 When combining antibiotic treatment with probiotic supplementation, it is recommended that the probiotics are taken a few hours after the antibiotics in order to optimize the effect.
The clinical effect of some different probiotic strains has been studied in human clinical trials; however, these results cannot be extrapolated to all probiotic strains and products, therefore, caution must be exercised when choosing a probiotic product.
Click to read more about what to look for when choosing a probiotic product
You can also read about the extensively studied Chr. Hansen strains here.
LGG®, GR-1®, BB-12®, RC-14®, TH-4®, and L.CASEI 431® are registered trademarks of Chr. Hansen A/S.
The article is provided for informational purposes regarding probiotics and is not meant to suggest that any substance referenced in the article is intended to diagnose, cure, mitigate, treat, or prevent any disease.