Probiotics have become a hot topic in medicine in recent years.  The WHO defines probiotics as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host”2

There has been a huge surge of research done on these critters over the past several years, all seeking answers to their role in human health and disease.  And it’s no surprise as to why:

Our gut is host to over 100 trillion individual bacteria, coming from more than 500 species.  There are more bugs in us and on us than there are cells that make us up1,3,5.  As I often say to my patients:

They are the boat.  We are the passenger.”

Our bugs outnumber us 10 to 1.  It’s astounding.  Why have we evolved in concert with them?  Do our bugs play a role in our health or disease?  If so, have we impacted them in a positive or negative way through our choices and activities (diet, lifestyle, urban versus rural living, medication use, antibiotics, exercise, etcetera)?  Can we manipulate our microbiome to serve a health outcome?

These are just a few of the basic questions researchers are asking about our bug-filled bodies.  And despite the thousands of scientific publications coming out yearly on our microbiome, we still know very little about it.  (The microbiome refers to the entirety of microorganisms, including their genetic material, living on and in the human body).

From the literature, we do know the following1-7:

  1. The microbiome plays a key role in human health and disease.
  2. Evidence suggest probiotics are beneficial, but the benefits are strain specific.
  3. Probiotics are generally considered safe, although chronically ill or elderly patients should consult a doctor knowledgeable in probiotics prior to use.
  4. Although research is promising, much more is needed.

Using the available scientific and clinical research, I regularly prescribe probiotics in my practice for various health concerns: gastrointestinal, immune, metabolic, endocrinological, neurological, and the list grows as more research is published!

But this post is not about the health benefits of probiotics — that’s a book for another day.  This post is about Why a probiotic won’t work, and what you can do to correct that.  Much of it, has to do with the point of purchase.

Buyer Beware!

From their debut on centre stage, supplemental probiotics have flooded the market.  Health food stores, pharmacies and grocery stores have whole shelves devoted to them with product companies making various claims in their marketing:

  • “Complete Probiotic!”
  • “Multi-strain formula!”
  • “Contains Pre-biotics!”
  • “Billions of live cultures!”
  • “Shelf-stable formula!”
  • “Proven for optimal digestive and immune health!”
  • “Eases IBS Symptoms!”
  •  and the list goes on…

Where does this leave you as a health-conscious consumer?  Are these claims accurate and how do you know that what you’re getting is any good?

Probiotic Myth-Busting: Why a probiotic won’t work2,3,5,6


The research is unclear at this point whether a multi-strain formula is better than a single strain one.  Some studies point one way, while other studies point the other.

Rather than focus on the number of strains, focus on what you are trying to achieve and choose a product whose strains are proven to do that.

For example, if you suffer from digestive stress and are wanting to support your gut integrity, choose a product with probiotic strains researched and proven to do just this.  If you want weight management, select for probiotic strains scientifically shown to help optimize weight balance.

What matters is the science.  There is a solid body of scientific and clinical research emerging about specific strains for the use in specific health concerns1-7.  Choose the right strain for the job.  Think of it this way: a mop is a great tool for mopping your floor but terrible for fixing your computer!  Right?!


The number of live cultures, or potency, needed in a probiotic is also up for debate in the literature2,3,5-7.  Again, choose the potency based upon what you’re trying to achieve.  Consult the scientific literature first and select a product that has the correct probiotic strains in the correct potency for what you need.  Life lesson: a really big hammer doesn’t necessarily hit the nail any better than a small one does.


No, not necessarily.  A good formula has scientifically proven strains, grown the right way, in the right potency, with proper manufacturing practices to ensure the probiotics’ efficacy.

Prebiotics are food for our probiotics.  So naturally, one would think that including them in a probiotic supplement makes for a better product.  But many people react negatively to the prebiotics included in a formula.  This makes the formula intolerable and therefore unusable.

Although needed, prebiotics can often be supplied through a fibre-rich diet.  And truth be told, fibre is a component seriously lacking in the western diet.  When it comes to prebiotics, ask your Naturopathic Doctor whether or not you need this in your probiotic formula or whether you could benefit from more fibre in your diet in general.


Absolutely not.  Acidophilus is a species of the genus, Lactobacillus.  In the Lactobacillus acidophilus group of bacteria, there are numerous strains and there are all different.  Few of the strains have been researched to demonstrate any health benefit whatsoever.  Buyer beware!

Choose strains backed by research.   A good quality probiotic will name the specific strain (not just the genus and species) in the formula.  But even with that, ensure the strain itself has scientific and clinical research behind it before you use it.


Not at all.  Purchase only probiotics that guarantee their potency at EXPIRATION.  This is the only way you can ensure a stable and effective probiotic from start to finish.  The product should state number of CFU’s (colony forming units, meaning live micro-organisms) at time of expiry.


Different probiotic strains have different temperature requirements.  Again, it comes down to the fact that not all probiotics do the same thing.  What are you wanting to achieve from this medicine?  The strain you choose for the job will have specific temperature requirements.

Some strains require refrigeration while others require room temperature.  Follow the manufacturer’s recommendation regarding temperature for storage to ensure you maintain a viable product.


  1.  The probiotic has human-sourced strains (not bovine, porcine or other animal).
  2.  The probiotic strains are backed by scientific and clinical research.
  3.  The strains are clearly labelled on the bottle.
  4.  The potency is labelled as number of CFU’s and the CFU’s are guaranteed at expiry.
  5.  The probiotics are allergen and contaminant free (dairy-free, gluten-free, non-GMO,  free of harmful bacteria, mold or yeasts, etcetera).
  6.  The company has met quality and purity measures for every product and testing certifications are accessible to you as a consumer.

If you have questions about whether a probiotic is a good choice for you, and what specific strains you may need, please call the clinic.  I am happy to help where I can.

  1. Anonymous. 2008-.  The NIH Human Microbiome Project.  Accessed online May 2020.
  2. Araya, M. et al2002. A joint FAO/WHO working group on drafting guidelines for the evaluation of probiotics in food report.  World Health Organization.  Accessed online May 2020.
  3. Knight, R.  2017.  The microbiome.  Metagenics Clinical Podcast.  Accessed May 2020.
  4. Mack, D. 2005.  Probiotics: mixed messages.  Canadian Family Physician, 51(11):1455-1457.  Accessed online May 2020.
  5. Patno, N. 2019. Probiotics nutrition masters course. Metagenics Institute.  Accessed online May 2020.
  6. Ruscio, M. 2017.  Applying microbiome science to clinical practice.  Metagenics Clinical Podcast.  Accessed May 2020.
  7. Sanders, M.  2017.  Latest understanding of probiotics.  Metagenics Clinical Podcast.  Accessed May 2020.