December 23, 2020

Prebiotics vs Probiotics

Prebiotics vs Probiotics: What's the Difference?

What is the key to having a healthy gut? To many people, gut health is still a big question mark. As more funding and scientific interest funnels into solving this gut microbiome health mystery, one major component to a healthy gut has taken center stage: bacteria. Bacteria may have a slightly bad reputation, but our bodies contain a large number of beneficial bacteria that are essential for gut health. Sometimes the good bacteria in your gut need some help to keep your gut functioning optimally. This is where probiotics and prebiotics come in. Whether you consider yourself a gut health guru or have never heard of a probiotic or prebiotic, stick around to discover the difference between prebiotics vs probiotics and how each can assist your gut and your overall health. 

Our Magical Gut Bacteria

To understand the different functions of probiotics and prebiotics, we first need to understand gut bacteria. Our entire lives, we’re taught to fear bad bacteria. Soaps, sprays, and hand sanitizer fill our supermarket aisles marketing their bacteria-killing abilities and we eagerly fill our carts with these products. Especially in 2020, we all want to do our best to stay healthy and we have convinced ourselves that stripping our bodies and our spaces of bacteria is the answer. Contrary to popular belief, there are good (or healthy) bacteria too, and they’re the key to healing your gut health. 

Gut bacteria can be found in the gastrointestinal tract (1). Our gut thrives off of beneficial bacteria and requires these bacteria to achieve optimal gut health. Our gut microbiome helps the body by breaking down food and aiding digestion, regulating inflammation, and boosting the immune system. Collectively all of the 100 trillion bacteria in your digestive system are known as the gut microbiota, but not all of the microbes found in your digestive system are good (2).

An imbalance in unhealthy and healthy microbes occurs when there are unhealthy levels of certain harmful  bacteria in your gut. A digestive system that has an overgrowth of “bad” bacteria or a deficiency of helpful bacteria is in a state of imbalance called dysbiosis. This can result in detrimental digestive system symptoms or increase the risk of other issues. To rebalance the microbes, sometimes the gut needs a boost from tools outside of the gut. Cue probiotics and prebiotics. 


Fun Fact: Probiotics are live microorganisms (2).  Most probiotics contain microbes that thrive within the body in areas such as the small intestines and colon. Once probiotics have entered your digestive system, they thrive in the gut and provide health-promoting benefits. When your body has a detrimental imbalance of bad bacteria and good bacteria, probiotics can restore your gut to a healthy state—in the battle between the good bacteria and bad bacteria, probiotics are the extra flanks of soldiers you can send in to bolster your existing army. 

There are 20 known species of probiotics and each probiotic species provides a distinctive health benefit (3). Furthermore, we can ingest probiotics in different ways as well. Probiotics can be consumed in both fermented foods and dietary supplements (4). It is important to note that not all fermented foods have probiotics, but many nutritionists recommend ingesting your probiotics in whole-food form as it is the most natural way to incorporate probiotics into your diet. Foods that are fermented go through a process of lacto-fermentation in which natural bacteria feed on the sugar and starch in the food, creating lactic acid. This process creates an environment that preserves the food and promotes beneficial enzymes, B vitamins, and omega-3 fatty acids, as well as various species of good bacteria. Some probiotic foods include yogurt, kombucha, and other fermented foods like sauerkraut and kimchi. In terms of supplements, scientists have found a way to isolate microorganisms from humans and then culture those microorganisms in a lab (1).


Instead of providing additional good bacteria, prebiotics provide your existing gut bacteria with the food and nutrients they need to flourish and grow (1). Essentially, prebiotics serve as a kind of “metabolic fuel” for your good bacteria. Prebiotics are non-digestible, specialized plant fibers that cannot be broken down by the digestive tract, so they make it to the colon where the good bacteria can use them as fuel (5). 

By eating a diet rich in variety, people can ensure that they consume a diverse set of prebiotics that nourish various types and strains of bacteria. Different fruits, whole grains, and vegetables contain different prebiotics that feed different good bacteria. For example, garlic specifically promotes the growth of Bifidobacteria in the gut while wild blueberries have been shown to induce improvement of Actinobacteria. 

Comparing Probiotics and Prebiotics

So all in all, what’s the difference between prebiotics and probiotics? Although both prebiotics and probiotics aim to better your gut and assist in balancing your good bacteria and your bad bacteria, prebiotics serve a completely different purpose than probiotics do. Bottom line: Probiotics are live microorganisms that you can ingest and they act as good bacteria in your digestive system. The buildup of good bacteria ultimately aims to restore the balance of good bacteria and bad bacteria in your gut. Prebiotics are not living. Prebiotics are ingested and serve as food for the good bacteria in probiotics as well as the naturally-occurring good bacteria in your gut, helping them to flourish and survive. 

How Probiotics and Prebiotics Work Together

When combined, probiotics and prebiotics make a mean, clean gut-health machine. When you combine a probiotic with its food source, the prebiotic, it has a much better shot at staying viable until it reaches the large intestine where it will ultimately inhabit and thrive. When it comes to gut health, taking a prebiotic and probiotic together can be an incredibly smart and healthy decision. These products have the “good” bacteria (probiotics) and the non-digestible carbohydrate source (prebiotics) to encourage the growth of beneficial bacteria (3)

Commercial products containing both prebiotic sugars and probiotic organisms are often called “synbiotics.” Synbiotics are known to improve the viability of probiotics (6). Synbiotics were developed to overcome possible survival difficulties for probiotics. Fermented dairy products such as yogurt are symbiotic because they have both the live bacteria and the food sources they need (3).

Indulge Your Curiosity

The history of probiotics and prebiotics is long, rich, and far too interesting to leave out. The initial notion of probiotic micro‐organisms can be traced to a century ago when the Nobel Laureate Ilya Metchnikoff noticed that the long healthy life of Bulgarian peasants resulted from the consumption of fermented milk products (7). The term probiotics is derived from a Greek word meaning “for life” (6). Although the idea of probiotics is far from new, the official definition of both a probiotic and a prebiotic was presented by Gibson and Roberfroid in the Journal of Nutrition in 1995. Being relatively new to the scientific community, there is still so much to learn about the effects and potential benefits of probiotics and prebiotics. 










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