Probiotics: Fact and Fiction
Did you know that you are more ‘alien’ than ‘human’? Your body contains up to ten times more bacteria than human cells. Probiotics, which are living microorganisms, play a key role in supporting your microbiome and overall health. However, as probiotics have gained popularity, myths and misinformation have spread, often fuelled by companies taking advantage of consumers’ lack of knowledge (10).
To assist in debunking the most common myths about probiotics, we aim to help you make informed decisions and save you wasting money, time and frustration.
Myth: All probiotic strains are the same.
Fact: Only a small number of probiotic strains have been clinically proven to support human health. Each strain has unique effects, and extensive research exists for only a few (1).
What is a “strain”? Probiotics are often identified by genus and species (e.g., Lactobacillus acidophilus), but each species contains multiple strains, each with distinct health benefits2. For instance, L. rhamnosus GR-1® and L. reuteri RC-14® are strains specifically linked to women’s health*(3).
As a rule of thumb, we approach probiotic strains as similar to the dog world – each strain may play a different function within the body. For example, you wouldn't strap a chihuahua to a harness and expect it to drag a sled in the snow alongside other chihuahuas - or expect a Great Dane to function as a lap dog. Pick the right species for the right job and it can be helpful. For the chronically constipated Mutaflor's Escherichia coli strain Nissle 1917 may be indicated (4), whereas antibiotic induced diarrhoea may call for Saccharomyces boulardii to slow down transit times and for its drying effect (5). Hence why it is always best to ask for advice based on current symptoms and goals.
Myth: High-quality probiotics don’t need temperature control.
Fact: Probiotics are living organisms, and their viability depends on a suitable environment. Heat and moisture can degrade probiotics, reducing their potency and health benefits. While some strains are shelf stable and do not require refrigeration, many will.
Protecting probiotics from heat:
While refrigeration isn’t always required, it’s often the best way to maintain potency over time. Each manufacturer will provide storage safety guidance depending on the strain.
Reputable brands ship probiotics with ice packs to protect them during transit. Even if the ice melts, the packaging typically keeps the temperature safe for the bacteria.
Packaging matters: Amber glass bottles prevent UV damage, and desiccant packets reduce moisture (7).
Myth: More CFUs mean “better results”.
Fact: The effectiveness of probiotics depends on specific strains and their clinically studied colony-forming unit (CFU) levels—not just higher numbers.
Research typically determines the optimal CFU count for a particular health benefit8. For example, if studies show benefits at 10 billion CFU for a specific strain, products should match this dosage. Claims of higher CFU counts offering greater benefits may lack scientific support.
Myth: Potency at production equals potency at expiration.
Fact: Some manufacturers highlight CFU counts at production but don’t guarantee the same potency by expiration. Probiotics can lose effectiveness over time, especially under improper storage conditions.
Products with potency guaranteed through expiration ensure reliable benefits throughout their shelf life. Look for labels that state this guarantee, along with proper usage and storage instructions. This ensures compliance with the Best Practices Guidelines for Probiotics from the Council for Responsible Nutrition (CRN) and the International Probiotics Association (9).
References:
National Center for Complementary and Integrative Health. Probiotics: In Depth. https://nccih.nih.gov/health/probiotics/introduction.htm. Accessed May 3, 2019.
National Institutes of Health. Probiotics. https://ods.od.nih.gov/factsheets/Probiotics-HealthProfessional/. Accessed May 3, 2019.
Köhler GA et al. Infect Dis Obstet Gynecol. 2012;2012:636474.
Mutaflor, About Mutaflor.
Szajewska H, Kołodziej M. Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea. Aliment Pharmacol Ther. 2015 Oct;42(7):793-801. doi: 10.1111/apt.13344. Epub 2015 Jul 27. PMID: 26216624.
Govender M et al. AAPS PharmSciTech. 2013;15(1):29–43.
Fenster K et al. Microorganisms. 2019;7(3):83.
Sniffen JC et al. PLoS One. 2018;13(12):e0209205.
Best Practices Guidelines for Probiotics. Council for Responsible Nutrition. https://www.crnusa.org/self-regulation/voluntary-guidelines-best-practices/best-practices-guidelines-probiotics. Accessed April 18, 2019.
Metagenics, 2019, Probiotics Facts & Myth.
