Probiotics vs. Prebiotics - What's the Difference?

Have you heard about probiotics? What about prebiotics? Do you know the difference?

Although they sound similar, there is an important difference between pro- and prebiotics. Both prebiotics and probiotics are essential for a healthy gut environment, or microbiome. While we are still discovering what exactly our microbiome does, we do know that there are certain characteristics of it that are associated with positive health outcomes (find out more here). This is why it is so important that we do our best to foster a healthy gut environment.

The simplest explanation is that probiotics are the microbes (we are usually talking about bacteria here) that colonize the large intestine, while prebiotics are the food, or fuel, which feeds those microbes.


Where do we find probiotics?

Probiotics can be obtained by taking probiotic supplements directly or by eating foods which naturally contain these microbes. These foods include:

  • Yogurt with “live or active (probiotic) cultures” or homemade yogurt.
    • Check the ingredients list for bacterial cultures such as Lactobacillus rhamnosus, L. casei, L. acidophilus, and Bifidobacterium lactis.
  • Kefir - a milk-based cultured by bacteria and yeast.
  • Sauerkraut - a fermented cabbage dish, often eaten with sausages or as a side dish.
  • Fermented vegetables - similar to sauerkraut but made with a variety of different vegetables.
  • Miso - fermented soybean paste used in soups or sauces.
  • Tempeh -fermented soybeans, formed into a firm block. It is rich B12 and protein, and used as a meat substitute.
  • Kimchi - a spicy, fermented cabbage dish from Korea.
  • Kombucha -a tea fermented with yeast and bacteria.

If you are interested in taking a probiotic supplement, it’s best to talk to a knowledgeable healthcare provider, as different health conditions benefit from different probiotic strains and dosages. Probiotic supplements are not one size fits all.


Where do we find prebiotics?

The good news is that the food that fuels the microbes in our gut, are part of the very foods we consume. This means that you don’t need to eat special foods in order to nourish your gut. The friendly microbes of our microbiome thrive on the fiber in our diet, particularly that of fermentable fibers.

The most common prebiotics are Fructans (fructo-oligosaccharides and inulin)galacto-oligosaccharides and resistant starches. Say what? Don’t worry, you don’t have to remember those tricky names...let’s just review the foods in which they are found:


  • Wheat, barley, rye, oats
  • Onions, leeks, shallots
  • Garlic
  • Bananas (ripe)
  • Chicory root
  • Jicama
  • Jerusalem artichoke
  • Inulin
  • Endive
  • Artichoke
  • Grapefruit
  • Nectarines and peaches
  • Persimmon
  • Watermelon
  • Dried fruits (apricots, dates, figs, mangos, and raisins)


  • Legumes and pulses (e.g. lentils, chickpeas/garbanzo beans, kidney beans, black beans, soybeans, split peas, and navy beans)
  • Green peas
  • Cashews
  • Pistachios
  • Silken tofu

Resistant Starches:

  • Legumes
  • Whole grains
  • Starchy vegetables
  • Bananas (unripe) and plantains
  • Corn
  • Potatoes and rice (especially when they have been cooked, then cooled)
  • Oats (both cooked and uncooked, but uncooked oats have a greater amount)

Our main goal with it comes to feeding our gut (or intestinal microbiome) is to provide it with sources of good bacteria/microbes (via probiotic foods) and fermentable fibers (prebiotics). While there aren’t any specific dietary recommendations regarding how much of each probiotic or prebiotic to be consuming, it’s probably a good idea to include some of these each day. s

Just a side note for those of you with IBS, following the Low FODMAP diet, both the fructan and galacto-oligosaccharide categories of foods are avoided (for the most part) during the elimination period of the diet. We do know that gut microbiota changes after a period of following the Low FODMAP diet and there is a very good chance that is from restricting prebiotic foods. This is why it is so important to follow through with the reintroduction phase of the diet. We need to find out which of these prebiotic foods our body tolerates, so that we can continue to feed those good little microbes in our gut.