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The difference between prebiotics & probiotics: do they help with dysbiosis?

Meet your gut-microbiome

The gut microbiome consists of a wide variety of bacteria, viruses, fungi and other microorganisms which reside in the digestive tract. There are 10s of trillions of microorganisms that live in your gut, some of which are beneficial to the body whereas others can be harmful. Research estimates that there are around 10 times more microbial cells in the body than human cells. Bacteria with beneficial qualities are called probiotics.


These bacteria work in a symbiotic relationship with the body, playing an important role in weight loss, digestive system health, mental health, and immune function. Pathogenic bacteria, on the other hand, are harmful to the body and can bring about digestive discomforts such as bloating, cramping, diarrhea, etc. When an imbalance occurs between the beneficial and pathogenic organisms present in a person's natural microflora, we consider the gut to be in a state of 'dysbiosis'. When this happens, certain pathogenic bacteria can flourish out of control. Dysbiosis can contribute to a range of conditions of ill health, inducing chronic fatigue, digestive problems, infections, skin conditions, inflammation and aching joints.

Source: Canadian Digestive Health Foundation


The 3Ws of probiotic supplementation (what - when - why)

The "what"

Probiotic supplements contain the beneficial bacteria that we generally want present in the digestive tract in large numbers. Prebiotic supplements contain the nutrients that these bacteria need to grow and thrive. Bacteria multiply very quickly but they need enough food and protection to survive the trip through the stomach and into the intestinal tract which is why many probiotic supplements also include prebiotics.


The "when"

The pattern of bacterial strains in the gut is quite different from person to person and is greatly influenced by diet. Those who consume a high fibre and low meat diet tend to have more stable colonies of bacteria than those who consume a diet high in meat and processed foods. The delicate balance of the microbiome is also easily upset by the use of antibiotics, the birth control pill, and steroid drugs. Supplementing with a probiotic can help both to maintain microbial balance in the gut and re-establish it once it has been lost.  Re-inoculating the gut through probiotic supplementation is an important step in any gut reset protocol.


The "why"

Probiotics exert health effects by nonspecific, species-specific, and strain-specific mechanisms. The nonspecific mechanisms vary widely among strains and species of commonly used probiotic supplements. These beneficial mechanisms include the inhibition of the growth of pathogenic microorganisms in the gastrointestinal tract (by fostering colonization resistance, improving transit, or helping normalize a dysbiotic microbiota), the production of bioactive metabolites (short-chain fatty acids), and the reduction of the pH in the colon. Species-specific mechanisms can include vitamin synthesis, gut barrier reinforcement, bile salt metabolism, enzymatic activity, and toxin neutralization. Strain-specific mechanisms, which are rare and are used by only a few strains of a given species, include cytokine production, immunomodulation, and effects on the endocrine and nervous systems. 


Of the 400 species of microflora living in the human intestinal tract, the two beneficial species that are most important are lactobacillus acidophilus (L. acidophilus) and bifidobacterium bifidum (B. bifidum). Lactobacillus acidophilus is the major colonizer of the small intestine and Bifidobacterium bifidum inhabits the large intestine and vagina. Lactobacilli produce lactic acid by fermenting carbohydrates. Lactic acid improves digestion by enhancing intestinal peristalsis and hindering the proliferation of harmful micro-organisms. At least 26 kinds of pathogenic bacteria are inhibited by L. acidophilus, including E. Coli, Salmonella, Staphylococcus, and Streptococcus. L. acidophilus also helps improve immune response to infection by increasing the activity of macrophages and lymphocytes. Bifidobacterium bifidum helps in the synthesis of B vitamins, in food digestion, as well as in inhibiting the growth of the pathogenic coliform bacteria.


Understanding your probiotic label

Probiotics are measured in colony forming units (CFU), which indicate the number of viable cells. You may sometimes see amounts written on product labels as, 1 x 10 for 1 billion CFU, for example. Most probiotics supply between 1 billion and 25 billion colony forming units (CFUs). It's important to note that a larger amount of CFUs is not always better, and that the therapeutic dose can vary based on the condition or symptoms being treated.

Probiotics are identified by their specific strain, which includes the genus, the species, the subspecies (if applicable), and an alphanumeric strain designation. Current labeling regulations only require manufacturers to list the total weight of the microorganisms on probiotic products’ Supplement Facts labels; this cellular mass can consist of both live and dead microorganisms and, therefore, has no relationship with the number of viable microorganisms in the product. Supplement labels typically include an expiration date as probiotics can lose their potency with time.

Source: Wix


Important things to know when choosing a probiotic

When choosing a probiotic, what matters is whether the product contains viable organisms that adhere to the gut lining, are not destroyed by bile, and have benefits once in your body. It is important to consider whether the probiotic has good tolerance to acidic conditions in order to survive the stomach and make it to its intended point of action. The probiotic also needs to be able to attach to the epithelial lining of the gut in order to form a colony.


The compression pressure used in chewable tablet production can decrease the probiotic cell count and viability dramatically, therefore a capsule form is preferred. Capsules can be opened and the probiotics mixed into food or a drink if unable to swallow capsules. High quality probiotics are freeze-dried, as freeze-drying puts the bacteria into suspended animation, keeping them dormant until they reach your body or are exposed to water.


Choosing an appropriate supplement is challenging, as research is still ongoing and it is important to use well-researched probiotics that have been found useful in clinical settings. Because the effects of probiotics can be specific to certain probiotic species and strains, recommendations for their use needs to be based on species and strain specific studies. Pooling data from studies of different types of probiotics can result in misleading conclusions about their efficacy and safety.

Other factors involved in the decision process include: differences in manufacturing processes and quality control of the products and, differences in international regulatory requirements. To ensure consistent high quality of strains, it's important to purchase supplements from a brand with a good quality control program in place to assure the consistent quality of everything, from ingredients to final product.


For this reason, you should always speak with a health professional before starting on a new probiotic supplement. In navigating the world of probiotics, the guidance of a healthcare provider ensures a personalized and informed approach. Our role as your health professional is to do all of the research for you and provide you with the best recommendations so that you don't have to guess at what strain or dosage you should be taking as well as the appropriate duration of use. Taking proactive steps to understand and support your gut health is important to overall health and well-being. If you're wondering whether probiotic supplementation might be of benefit to you, schedule a free discovery call with holistic nutritionist Kim or send Kim a message.

Brands we trust

If you're eager to start your search of a high quality and reputable brand for pre and probiotics, let me help put you on the right path. The following brands offer a variety of well researched probiotic supplements:

Tip: Probiotic Guide Canada is also a great app to reference if you're looking to learn more about the clinical trials completed on various probiotics. The guide is designed to translate scientific evidence available for probiotic products to practical, clinically relevant information and is updated annually to reflect current research.




Cooper, J. (2023) ‘How to choose an effective probiotic’, Atrium Innovations On Demand Series. Online: 13 November 

Lipski, E. (2020). Digestive wellness: Strengthen the immune system and prevent disease through healthy digestion (5th ed.). McGraw-Hill.

Office of dietary supplements - probiotics. (2023). Retrieved from

Papaconstantinou, J. (2022). Symptomatology . Lecture, Toronto: Institute of Holistic Nutrition

Rowland, D. (2020). Nutritional Solutions for 88 conditions. S.l.: LAP LAMBERT ACADEMIC PUBL.

The Production and Delivery of Probiotics: A Review of a Practical Approach. (2019). Retrieved from


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