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Prebiotics and Probiotics

By Erin Appleton

You may have heard about probiotics from a friend or seen the shelves of prebiotics and probiotics in the supplement aisle of the grocery store. But what exactly are prebiotics and probiotics? 

a breakfast bowl, a pineapple, a probiotic bar and a spoon

Prebiotics and probiotics help maintain the health of what is known as your gut microbiome, in other words, the community of helpful bacteria that live in the gut. There are many different types of helpful bacteria which do a variety of important things for our bodies such as aiding in digestion1,2, producing vitamins (B vitamins and vitamin K)2, and preventing the growth of disease-causing bacteria2. Prebiotics are food for these helpful bacteria whereas probiotics are the helpful bacteria themselves. 


Prebiotics are plant fibers that the human body is not able to fully digest. Instead, these plant fibers are digested by helpful bacteria in the gut1,2. This helps nourish not only the bacteria but also us! When our helpful bacteria digest these fibers, they produce substances we can use for energy1,2. Prebiotics are found naturally in many different fruits and vegetables, especially those that contain fiber. Examples of fruits and vegetables high in prebiotics include bananas, onions, garlic, asparagus, and artichokes3. Prebiotics can also be found in beans and whole grain foods3.


Probiotics are live bacteria that are beneficial for our gut microbiome. Probiotics can be used to help keep the community of helpful bacteria in our gut well-populated and balanced. Like prebiotics, probiotics can also be found in the diet. Probiotics are found mainly in fermented foods such as yogurt, kefir, and aged cheese3. Non-dairy foods that contain probiotics include kimchi, kombucha, sauerkraut, miso, and tempeh3. 

Examples of when it might be helpful to consume more prebiotics and probiotics:

  1. During and after taking antibiotics. While antibiotics kill the bacteria that make us sick, they also kill the helpful bacteria found in the gut. This can cause an imbalance in our gut microbiome that can cause gastrointestinal upset. Consuming probiotics may help repopulate the helpful bacteria in your gut3.

  2. If you experience frequent gastrointestinal upset (such as abdominal cramps, constipation, diarrhea) and/or have Irritable Bowel Syndrome (IBS). Evidence suggests that the use of probiotics may help improve IBS symptoms4,5. 

Thinking of taking a prebiotic or probiotic supplement?

Talk to your doctor first! Ideally, you should always talk to your doctor before taking a new supplement or medication. Also, there are many different types of prebiotic and probiotic supplements available and your doctor or registered dietitian can help decide which is best for you. Before trying supplements, a great first step is to consume more prebiotics and probiotics in your diet and see how it makes you feel. 


  1. Valdes, Ana M, Walter, Jens, Segal, Eran, & Spector, Tim D. (2018). Role of the gut microbiota in nutrition and health. BMJ, 361, K2179.

  2. Jandhyala, Sai Manasa, Talukdar, Rupjyoti, Subramanyam, Chivkula, Vuyyuru, Harish, Sasikala, Mitnala, & Nageshwar Reddy, D. (2015). Role of the normal gut microbiota. World Journal of Gastroenterology : WJG, 21(29), 8787-8803.

  3. Klemm, S. (2020, June 9). Prebiotics and Probiotics Creating a Healthier You. Eatright.

  4. Abdollahi, T. D. (2015). Effectiveness of probiotics in irritable bowel syndrome:Updated systematic review with meta-analysis. World Journal of Gastroenterology : WJG, 21(10), 3072-3084.

  5. Ford, Alexander C, Harris, Lucinda A, Lacy, Brian E, Quigley, Eamonn M. M, & Moayyedi, Paul. (2018). Systematic review with meta-analysis: The efficacy of prebiotics, probiotics, synbiotics and antibiotics in irritable bowel syndrome. Alimentary Pharmacology & Therapeutics, 48(10), 1044-1060.

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