Prebiotics: Beneficial Effects for Digestive Health and Wellbeing

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In recent years, gut health has taken centre stage in conversations about nutrition and overall wellness—and for good reason. A well-functioning digestive system is vital for overall health. One key player in this digestive wellness equation is prebiotics. While probiotics and prebiotics sound similar, they each play a very different role in gut health.  Read on to learn more about the important differences between probiotics and prebiotics and how prebiotics benefit overall health!

What are probiotics?

The International Scientific Association for Probiotics and Prebiotics (ISAPP) define probiotics as, “Live microorganisms that, when administered in adequate amounts, confer a health benefit on the host” (1).   So, probiotics are considered live beneficial bacteria that can provide a benefit to our health when adequate amounts are consumed. 

Probiotics are identified by their specific strain, which includes the genus, the species, the subspecies (if applicable), and a strain designation.  For example, the probiotic Bifidobacterium animalis lactis DN-173 010 consists of:

GenusSpeciesSubspeciesStrain Designation
BifidobacteriumanimalislactisDN-173 010

Each specific probiotic strain has been studied and each strain provides a very specific and unique health benefit.  For example, reducing antibiotic-associated diarrhea or managing irritable bowel syndrome (IBS) symptoms such as abdominal discomfort, bloating and gas.  The Clinical Guide to Probiotic Products Available in Canada  is a helpful tool to assist clinicians and consumers in understanding which probiotics have evidence for a specific indication.

You can find probiotics in supplement form or added to certain foods like yogurts or kefirs. 

What are prebiotics?

Unlike probiotics, which are live organisms, prebiotics are non-living and non-digestible components of food that feed the live beneficial bacteria in your gut.

Prebiotics are defined by ISAPP as: “A substrate that is selectively utilized by host microorganisms conferring a health benefit” (2). 

So, prebiotics act as an energy source for the bacteria in your gut.  Your bacteria ferment “eat” the non-digestible components of food, thereby supporting the growth of good healthy bacteria that in turn are linked to a beneficial health effect.

Most prebiotics are fibres, though not all fibres are prebiotics.  In order to be considered a prebiotic, the fibre must pass through the gastrointestinal tract undigested and stimulate the growth and/or activity of certain good bacteria in the large intestine (3). In addition to prebiotic fibres, research has also uncovered some additional candidate prebiotics including polyphenols and conjugated fatty acids, that also have prebiotic-like activity in the gut.

What are some prebiotic fibres?

Common prebiotic fibres include:

  • Inulin-type fructans (ITFs), which includes inulin and fructooligosaccharides (FOS)
  • Galactooligosaccharides (GOS) are another accepted prebiotic

What are some prebiotic benefits for overall health?

Most of the research to date focuses on ITFs.  A 2022 systematic review entitled, “The Prebiotic Potential of Inulin-Type Fructans” published in the journal Advances in Nutrition, was based on the results of human clinical trials in healthy adult populations.

This review suggests ITFs do have a prebiotic effect on the intestinal microbiota – the community of gut microbes residing in your large intestine – by promoting the growth and activity of bacteria with known beneficial effects, such as Bifidobacterium, Lactobacillus, and Faecalibacterium prausnitzii. These effects on the intestinal microbiota contribute to beneficial effects on human health.

Several beneficial health effects were reported following ITF intake such as:

This systematic review suggests that future research should focus on determining the mechanisms by which the intestinal microbiota mediates or modifies the effects of ITF on human health. As well, the impact of individual factors such as baseline intestinal microbiota composition, fibre intake, age or metabolic health status should also be considered when examining the effects of ITF intake on human health.

Where are prebiotics found?

Prebiotics are naturally found in many plant foods such as:

  • ITFs: leeks, garlic, onions, artichokes, bananas, asparagus
  • GOS: chickpeas, lentils, faba beans, fenugreek, soybeans

Prebiotics can also be added to some foods/beverages by manufacturers such as breads, snack bars, breakfast cereals, beverages, dairy products/alternatives, soups and sauces.  Check the ingredient label for words like inulin, chicory root/fibre, oligofructose and galactooligosaccharides to determine if a product contains prebiotics.

Prebiotics can also be found in supplement form. If you’re thinking about a supplement, remember it’s important to speak with your doctor before taking any supplement to make sure that you’re taking a supplement that’s right for you.

Tip:  Slowly increase the amount of prebiotic fibres in your diet and drink plenty of fluids as your intake increases to help the fibre work better and prevent gas and bloating.

Are there any contraindications for consuming prebiotics?

Although prebiotics have shown positive benefits for overall health, they may exacerbate symptoms in those with certain digestive conditions like irritable bowel syndrome (IBS). Many prebiotics are considered high FODMAP, so for those following a low FODMAP diet, prebiotics would not be advisable.

As well, those who are immunocompromised should always consult with their physician first, before making any dietary changes.

Remember: As with any dietary change, it’s important to consult with your healthcare provider to ensure it fits well with your overall health plan.

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