What is the role of strain specificity in choosing a probiotic?

By Melody Khorrami, PharmD, RPh, INHC

As consumer use of probiotics increases, the need for education around choosing the right probiotic combination and which strains are most valuable for specific health conditions is also expanding. When choosing the right probiotic, two important factors to consider are strain specificity and disease specificity as they relate to the usefulness for a particular medical condition. There is evidence to suggest that the practicality of probiotic use is related to both strain and disease specificity. 

What are probiotics?

Probiotics are defined as “live microorganisms that, when administered in an adequate amount, provide a health benefit to the host”. There are many different brands and strain combinations on the market, including a variety of colony-forming units. Colony-forming units (CFU) are the number of live and viable microorganisms in one serving of probiotic dietary supplements or medical food. CFU counts range from millions to trillions; however, most of the clinical data is in count ranges of billions.

Probiotics can support health in several different ways: they can help your immune system function properly, aid in digestion by helping to break down food, help produce vitamins and help with nutrient absorption, and assist with keeping harmful bacteria out. Since probiotics are live microbes they can impact the microbes that already reside in our body but they typically do not permanently remain in the gut. The way that probiotics generally provide their health benefits is by passing through the human gut and interacting with the immune and gut cells with which they come into contact. Keep in mind that every person’s body and bacterial composition is unique to them, so using products that are supported by science and having a goal in mind with your healthcare provider on why you want to use a probiotic is important. Probiotics can be used for general gut health maintenance, but doses will differ according to intended uses for specific health conditions. 

How to distinguish one probiotic from another: 

With so many different probiotics on the market, it is difficult to know which probiotic product to choose based on the specific health condition. The challenge lies in being able to differentiate one product from another based on the manufacturing process, quality control, and intended effect of the strain combinations in the product. Probiotics are identified by strain specificity, which includes the following components; genus, species, sometimes a subspecies, and the alphanumeric strain designation. With the introduction of genomic analysis, the role of strain specificity started to be taken into consideration. Various probiotic guidelines also started to make recommendations utilizing the specific strain designations from clinical trials.

It is important to note that just because a probiotic has a larger dose or contains lots of strains does not necessarily mean it is more effective.

Some studies point to single-strain probiotic products and their benefits for specific health conditions and others with better outcomes with specific multi-strain blends.  The effectiveness is best determined by clinical trials and the strain combinations and intake amounts used in those trials related to certain health conditions.   

Other challenges in choosing the right probiotic mixture are that while one mixture may be effective for one health condition it may not be effective for another. Intended uses for probiotics with clinical data range from use in antibiotic-associated diarrhea, irritable bowel syndrome, ulcerative colitis, pouchitis, hepatic encephalopathy, traveler’s diarrhea, skin conditions such as atopic dermatitis, vaginitis, and colic in babies.

When choosing a probiotic, it is important to look at the data related to that product in certain health conditions. The data should not only be related to genus and species but should include the distinct strains and amount taken during the clinical trials.  Choosing the right probiotic strain combination can be challenging and attention needs to be given to the specific strain and the disease or condition it is being used to treat. As a consumer, it is important to choose products that have strong clinical trial data. When in doubt you can call the product’s manufacturer to request scientific data on their exact product.  

Please note: This article was written for educational purposes only. Please consult your healthcare provider before making any changes to your healthcare plan.

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