Probiotics vs Prebiotics


This content was made possible due to an unrestricted educational grant from Activia.

There’s lots of talk about probiotics these days and their role in digestive health and disease. While probiotics and prebiotics sound similar, they are very different and have different roles in gut health. 

What are probiotics?  

As mentioned here in our probiotics vs fermented foods article, the Food and Agriculture Organization of the United Nations and World Health Organization (FAO/WHO) defines probiotics as “live microorganisms which when administered in adequate amounts confer a health benefit on the host.”1 In plain language, probiotics are “good bugs” or “good microbes” that improve certain aspects of our health. Each probiotic is unique, has a very specific intended purpose, with specific types or strains that can help manage certain specific conditions.2 These may include reducing antibiotic-associated diarrhea, managing IBS symptoms like bloating, and changes in bowel habits. These friendly microbes also help us digest fibre and other nutrients.  

Contrary to what you may think, probiotics don’t make their way into your gut and set up ‘camp’ but rather, have a ‘transient’ effect meaning that when you consume them, they do a specific job, and then they leave your gut.  

It’s important to note that not everyone needs to take a probiotic for general “gut health”. Certain probiotics have been identified as a treatment for specific conditions and symptom relief. It’s important that you talk with your doctor, pharmacist, or dietitian first before taking a probiotic, to ensure you have a proper diagnosis or know why you are taking it. Together, you can select an appropriate probiotic that is the most suitable for you. 

Once you do, you’ll find out that probiotics can be found in: 

  • Certain fermented foods including fermented milks like some yogurt and kefir 
  • Pill form  
  • Powder form 

What are prebiotics?  

Prebiotics are defined as “a substrate that is selectively utilized by host microorganisms conferring a health benefit.”3 In other words, they are food for our gut microbes. Prebiotics are indigestible parts of food that ferment in the gut and feed the good bacteria. The good bacteria then produce ‘short chain fatty acids.’ Short chain fatty chain acids play an important role in nourishing the cells of our gut barrier, contributing to a functioning immune system, and so much more.  

By getting enough prebiotics in our diet, we can improve the number and variety of bacteria in our gut – which supports better overall gut health.  

CDHF’s gut health expert and registered dietitian Andrea Hardy mentions that “when we don’t fuel our gut bacteria with enough prebiotics, bacteria have to find fuel from other sources. It’s been shown in animal models that bacteria will eat the all-important mucous layer in your gut – which is your first line of defence against invasion of potentially harmful compounds”.4 

Prebiotics can be naturally found in many foods like legumes, fruits, certain nuts, seeds and grains. In addition, there are several products on the market to which manufacturers have added prebiotics (for example: cereals, protein supplements, energy bars, and “healthier” cookies, to name a few).   

While most prebiotics are a type of fibre, not all fibres can be classified as a prebiotic, not all fibres can be classified as a prebiotic. Examples of prebiotic fibres include inulin, fructans and galacto-oligosacharides (GOS). Some foods that are naturally high in prebiotics are:  

Vegetables Jerusalem artichokes, garlic, onion, asparagus cabbage, snow peas, green peas, leeks, shallots 
Fruit Apples, grapefruit, pomegranate, nectarines 
Whole Grains Oats, wheat, barley, rye crackers 
Nuts and Seeds Pistachio nuts, cashews  
Legumes Red kidney beans, soybeans, chickpeas, lentils 

Dr. Frank W. Jackson, gastroenterologist – explains the difference between a probiotic and prebiotic with a helpful garden metaphor. “You can add seeds—the probiotic bacteria—while the prebiotic fibre is the water and fertilizer that helps the seeds to grow and flourish.”  

If you put that into the context of your body, while you are getting enough probiotics in your diet – do not forget about the prebiotics that feed the microbes that keep you healthy and happy every day! 

More of a Visual Learner? Download our Infographic

Want to learn more? See the other resources in this program:


  1. Hill, C., Guarner, F., Reid, G., Gibson, G.R., Merenstein, D.J., Pot, B., Morelli, L., Canani, R.B., Flint, H.J., Salminen, S., Calder, P.C., & Sanders, M.E. (2014). The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 11(8), 506-514.  
  1. Alliance for Education on Probiotics (AEProbio). (2021). Understanding probiotics. Retrieved March 6, 2021, from
  1. Gibson, G.R., Hutkins, R. Sanders, M.E., Prescott, S.L., Reimer, R.A., Salminen, S.J., Scott, K., Stanton, C., Swanson, K.S., Cani, P.D., Verbeke, K., & Reid. G. (2017). Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nature Reviews Gastroenterology & Hepatology, 14(8), 491-502.  
  1. Hardy, A. (2019). How prebiotics help gut health. Retrieved February 22, 2021, from