Probiotics vs. Prebiotics: Which One Should I Take?

by Sukhsatej Batra, Ph. D September 15, 2020

The importance of probiotics and prebiotics for health is a trendy topic as several products with these words on their labels become available in grocery stores. You may wonder whether this is just another food fad or something you really need to include in your diet to be healthy. One of the first questions you probably have is –what is the difference between probiotics and prebiotics?  This may be followed by - how important are probiotics and prebiotics for maintaining a healthy gut? Are there other benefits of taking probiotics and prebiotics? And if I have to choose between probiotics versus prebiotics: which one should I take?

Well, according to science, you need both. Even though probiotics and prebiotics sound similar and have only a one letter difference in their spelling, they play two completely different roles in the body. Let's dig deeper into this topic and learn more about what makes probiotics and prebiotics so important for maintaining human health.

Probiotics vs prebiotics: What is the difference?

To understand the difference between probiotics and prebiotics, we first have to look inside the digestive system. Did you know that the human gut is a microbiota or diverse ecosystem that is home to trillions of bacteria and other microorganisms? (1) These gut microbiomes or gut microflora are essential for maintaining human health and play major roles in the body including digestion of food, production of vitamins, protection against pathogens and boosting the immune system. (2)

In exchange for these health-promoting functions, most of the helpful bacteria live in your colon without you even knowing they are there! But you will notice a difference in your health if their number decreases. It is, therefore, important to maintain the population of the gut microflora to protect your health. This is when probiotics and prebiotics come to the rescue.

But what are probiotics and prebiotics? Let us first look at the definition of probiotic, which comes from the Latin word 'pro' meaning 'for', and from the Greek word 'biotic' that means 'life'. The Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) define probiotics as, “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host". (3)

Simply put, probiotics are foods or supplements containing live bacteria that, when taken by you, the host, promote your health.

The word prebiotic, on the other hand, refers to the food that the bacteria or probiotics in your gut feed on to survive. Prebiotics are a type of dietary fiber found in carbohydrate foods that cannot be digested by humans but are the food that the live bacteria need to grow and thrive.

Why you should take both probiotics and prebiotics

Prebiotics and probiotics play complementary roles in your body, with the prebiotics providing food for the good bacteria to grow and flourish so that a healthy gut microbiota is maintained. In the absence of prebiotics, the population of good bacteria in the gut will dwindle and create health problems that are not only limited to the digestive tract but your overall health as well.

These gut microbiota play vital roles in producing vitamins, absorbing minerals such as calcium, magnesium and iron, provide protection against pathogens, boost the immune system and ferment non-digestible foods to short chain fatty acids.(2) Some of the benefits of taking probiotics include treatment or prevention of diarrhea, Crohn's disease, Irritable Bowel Syndrome or IBS, skin conditions, vaginal infections and urinary tract infections.(4)

Although more research is needed, some literature suggests that probiotics may improve digestive health by reducing risk and improving the effectiveness of colorectal cancer treatment. (1,5)

Athletes, too, may benefit from taking probiotic supplements as it may promote a healthy immune system and reduce the severity and duration of upper respiratory tract infections. (3)

When you should not take prebiotics

Although prebiotics are an important part of good gut flora, there are specific instances where prebiotics can do more harm than good.  From our discussion, you understand that prebiotics are the food for the good bacteria (AKA probiotics).  However, prebiotics aren't only food for good bacteria, but also for unhealthy or "bad" bacteria.

If you are struggling with SIBO (Small Intestinal Bacterial Overgrowth), you will want to avoid prebiotics and prebiotic foods during this time.  You see, you have an overgrowth of bad bacteria in your gut.  What you want to do is starve out that bad bacteria by utilizing the proper supplementation and diet.  You do not want to feed the bad bacteria with prebiotics.  So for those with SIBO, skip the prebiotic all together and just utilize probiotics.

Food sources of probiotics and prebiotics

While there are many types of bacteria in foods, Lactobacillus and Bifidobacterium are two of the most common strains of live bacteria found in probiotic foods. Fermented foods are good sources of probiotics as they contain live strains of bacteria that increase the population of the good bacteria in your gut.

9 foods high in probiotics

When looking for probiotic foods, look for unpasteurized foods because pasteurization kills the bacteria. Some of the fermented vegetable products contain both prebiotics as well as probiotics, so that you get the live bacteria as well as the fiber that they need to feed on. Such foods are called symbiotic foods.

  • Yogurt with live, active culture
  • Kefir, a fermented milk drink that is similar to yogurt
  • Sauerkraut, made by fermenting cabbage
  • Kimchi, fermented cabbage and other vegetables
  • Tofu, a fermented soybean curd
  • Tempeh, a fermented soybean product
  • Miso, made by fermenting soybean and other grains
  • Kombucha tea, a tea fermented with bacteria
  • Unpasteurized pickle

For a starter guide on fermenting food in your own kitchen, click here.

List of prebiotic foods

When looking for prebiotic foods, it is important to remember that not all types of fiber are prebiotics. (6) Some good sources of prebiotic foods are listed below.

  • Garlic
  • Onions
  • Oats
  • Asparagus
  • Jerusalem artichokes
  • Dandelion greens
  • Bananas
  • Wheat bread with bran
  • Apples with skin
  • Chicory root
  • Leeks

Taking Prebiotics and Probiotic Supplements

While the list above may give you ample choice of foods to increase your intake of prebiotics and probiotics, you might want to take supplements to rapidly boost the number of gut bacteria. Remember that quality is very important in this situation. Live organisms are not able to withstand extreme temperatures.  Finding shelf-stable probiotics supplements, like those in individually, nitrogen sealed packs, help ensure that the organisms make it to your digestive tract alive and are able to be effective.

In Conclusion

Both probiotics and prebiotics are essential for an optimal functioning gut health and do not have to choose one over the other. Prebiotics are necessary for the survival and growth of probiotics and they work together to keep your gut microbiota strong and healthy.

Hopefully, you find some of the foods listed above inspiring and incorporate them in your diet to not only maintain a healthy gut but to improve your overall health as well.


Sukhsatej Batra, Ph. D
Sukhsatej Batra, Ph. D

Sukhsatej Batra has a Ph. D in Foods and Nutrition with a passion for motivating people to improve their well-being and achieve results through healthy lifestyle changes. Previously, Sukhsatej has worked as a Senior Research and Development Scientist and college professor.