What’s the Difference Between Probiotics and Prebiotics?

People use probiotics and prebiotics interchangeably, but they actually play very different roles in our gut and overall health. Here’s what you need to know.

The conversation surrounding gut health can be confusing, especially when its buzziest words (prebiotic and probiotic) sound practically identical. So what are prebiotics and probiotics, and what can they do for us? Let’s take a look.

What's the difference between prebiotics and probiotics?

Prebiotics are a form of fermentable fiber that have been studied since the 1990’s. By definition, they are a substrate that is selectively utilized by host microorganisms conferring a health benefit. In simpler terms, prebiotics are a specific kind of fiber that the good bacteria in our gut (the small and large intestine) seek out and feed on, and as a result we can experience health benefits.

A probiotic is a live microorganism (bacteria) that, when administered in adequate amounts, can result in a health benefit. These probiotics may influence the landscape of the microbiome in our gut by either maintaining or supporting the “good” bacteria that live there.

What are the potential benefits of consuming prebiotics and probiotics for gut health?

Prebiotics promote the growth of good bacteria, and probiotics can help to increase the diversity of bacteria in our gut microbiome. When the bacteria in our gut ferments fibers like prebiotics, they create a byproduct called short chain fatty acids. These short chain fatty acids play a crucial role in things like our immune system, digestion, regulating inflammation, and the brain-gut connection.

What foods contain prebiotics and probiotics?

Inulin & oligofructose are two examples of prebiotics that can be found in foods people commonly consume. They considered prebiotics because they have been shown to increase beneficial bifidobacteria in humans in several human intervention trials. You can find these prebiotics in foods like onions, asparagus, chicory root, artichoke, leeks and bananas. Probiotics, such as Lactobacillus bulgaricus, can be found in most yogurts available at the grocery store.

The probiotics from certain fermented foods like kimchi or sauerkraut may or may not be beneficial for us as they do not usually contain proven probiotics. That being said, there is lots of exciting research examining the benefits of fermented foods for our gut health.

A study from Stanford University in 2021 looked at participants who increased their fiber and participants who increased their fermented food intake. At the end of the 17 week period, those who increased their intake of fermented foods had an increase in microbial diversity at the end of the study as well as decreased inflammatory markers.

Should I be taking a prebiotic and probiotic supplement?

Not necessarily. These supplements can be expensive, and there are other ways you can incorporate prebiotics and probiotics into your diet. Sometimes people take probiotic/prebiotic supplements because it was recommended to them by their doctor, or they may just prefer taking them in supplement form. It’s all about what feels most attainable for you; the healthiest habits are the ones you can do consistently.