The gut microbiome: Deciphering prebiotics and probiotics



Although we usually tend to think about bacteria in a negative light, they aren’t all bad! The gut microbiome, a population of trillions of bacteria that resides in the gastrointestinal tract, plays vital roles in our body. Gut bacteria, otherwise known as microbiota or gut flora, are involved in the metabolism of nutrients and drugs, they help maintain the function of the intestinal barrier, and they are linked to various health issues including diabetes, obesity, irritable bowel syndrome, rheumatoid arthritis, and depression.


We all first acquire gut bacteria during birth and breastfeeding, and our microbiome is diversified based on our physical environment, diet, and use of antibiotics. Although everyone’s microbiome is unique and should be thought of as an ecosystem within our gut, the presence or absence of certain bacteria, as well as the balance between certain “good” and “bad” bacteria, can influence our health. Fortunately, if our gut microbiome is disrupted (usually by antibiotics) resulting in bad bacteria overtaking good bacteria, there are several options to change the gut environment back to having a beneficial profile.


While fecal microbiota transplants from healthy “donors” have been proposed as a treatment for those with severely disrupted microbiota, such as during C. difficile infection, (read all about it here:, less invasive options exist to ensure that your gut flora stays in optimal health, so you can too!  These fall into two categories: probiotics and prebiotics.



Probiotics are live bacteria that are ingested that contribute to the gut microflora. They are found in supplements at health food stores and in foods labeled as having “live cultures”, such as yogurt, cheese, kefir, kimchi, sauerkraut, and pickles. Consuming some of these beneficial bacteria can contribute to maintaining gut health as they are able to colonize the gut upon ingestion. However, the amount of probiotics required for various health benefits remains unknown. Potential benefits of consuming probiotics via supplements are that they are available in more concentrated doses and are sometimes packaged in enteric-coated capsules meant to withstand stomach acid. Keep in mind that research investigating their effects is still preliminary and that they differ according to the bacterial strains included (the most studied are Lactobacillus and Bifidobacterium), dosage, and the number of organisms included! While more research is required to fully understand the benefits of probiotics, the consensus of health professionals is that healthy adults can safely add probiotics to their diets to enhance their gut health.



Prebiotics are non-digestible carbohydrates that act as food for the bacteria already living in the gut. Eating prebiotics can increase the health of beneficial bacteria, which contributes to the overall health of the digestive system. Prebiotics are categorized into different classes, including fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS). Inulin is the most common FOS and in addition to being used as an additive in different foods including bread, breakfast cereals, and dairy products, it is naturally found in vegetables including artichokes, asparagus, garlic, and onions; grains including barley and rye; and roots, such as dandelion root. Eating prebiotics as foods or supplements on a regular basis will provide a continuous supply of “food” for your beneficial gut bacteria, enabling them to stay healthy and fight off bad bacteria.


When it comes to gut health, the bottom line is to consume a healthy diet that will provide natural sources of both pro- and pre-biotics! Eating vegetables, dairy, and fermented products will provide essential nutrients in addition to the fibre and live bacteria that will contribute to a happy and healthy gut!





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