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Probiotics and prebiotics. What is their difference and why it matters?


Probiotics:  Are defined as live microorganisms that, when administered in adequate amounts, confer a health benefit. Fermented foods such as yoghurt, sauerkraut, kombucha, tempeh, kimchi are probiotics.

Prebiotics: a food ingedrient that is non-digestible but stimulates the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves health. Prebiotics can be seen as the “fertilizer” for the “good“ bacteria which are already present in our gut. They include high-fiber foods such as chicory root, Jerusalem artichoke, legumes, peas, asparagus

Differences between probiotics and prebiotics and why are they important for our gut health

Although both probiotics and prebiotics sound similar, they shouldn’t be confused as they work in different ways in the gut.

probioticsThe main difference between the two is that probiotics are live microorganisms while prebiotics are food ingredients that can be digested only by the gut bacteria [1][2].

Our gut host trillions of tiny creatures known as microbes. These microbes rely on the nutrients they get from our diet to survive, meaning that, what we eat will determine which microbes will be present in our gut. This is important as within our gut we can find thousands of different microbes, some of which can be beneficial and some potentially harmful. For proper gut function, a well-functioning microbial community composed of beneficial microbes is essential. So, how can we promote the beneficial microbes in our gut? The answer is through the consumption of probiotics or prebiotics!

How can I get probiotics and prebiotics?

Fermented foods are a natural source of probiotics. Fermentation is an ancient technique to preserve food using microorganisms such as yeast or bacteria which are converting carbohydrates into acids and alcohol. The production of these compounds creates an environment that does not allow pathogens to grow and the food can be preserved for a longer period. To explain this better, we will use yogurt as an example. Yogurt is produced by bacteria that are added in the milk, known as Lactobacilli. These bacteria ferment milk lactose and “convert” it to lactic acid which gives yogurt its sour taste and unique texture. In this way, if you eat yogurt you are not getting only nutrients such as proteins, carbohydrates, and fat but also get the probiotic bacteria that produced the yogurt! The same process is happening also with the other fermented foods which are natural sources of probiotics, such as sauerkraut, kombucha, tempeh, kimchi, etc.

Prebiotics naturally exists in numerous plant-based foods that are high in fiber, such as chicory root, Jerusalem artichoke, legumes, peas, asparagus, etc. We as humans lack the enzymes to digest these fibers, and only the bacteria in our large intestine can use them. In a way, prebiotics are the “fertilizer” for the “good“ bacteria which are already present in our gut. Consumption of fiber is highly recommended to be part of a balanced diet and has been shown to improve gastrointestinal and cardiovascular health [3].  

Except from food, probiotics and prebiotics can be obtained from supplements that are commercially available. Probiotic supplements can contain one strain of microbe or a combination of microbes while prebiotic supplements contain fermentable fibers extracted from foods.

Do I need to buy supplements?

Keeping a diverse and well-functioning bacterial community in our gut is essential for gut health. A diet that includes fruits, vegetables, and fermented foods can provide us with sufficient amounts of prebiotics and probiotics to promote gut health without the need to buy supplements. Thus, if you are healthy maybe it is better to spend your money on healthy food than on probiotic or prebiotic supplements.

Finally, be aware that even though probiotics and prebiotics are considered to be safe, they might cause negative effects in people with weak immune system or interfere with medication. Hence, if you are considering taking prebiotics or probiotics targeting improvments in a specific disease or a condition, always ask for the advice of your doctor first.


  1. FAO/WHO, Evaluation of health and nutritional properties of powder milk and live lactic acid bacteria. Food and Agriculture Organization of the United Nations and World Health Organization Expert Consultation Report. 2001, FAO Rome, Italy.
  2. Gibson, G.R. and M.B. Roberfroid, Dietary modulation of the human colonic microbiota: introducing the concept of prebiotics. The Journal of nutrition, 1995. 125(6): p. 1401-1412.
  3. Kaczmarczyk, M.M., M.J. Miller, and G.G. Freund, The health benefits of dietary fiber: beyond the usual suspects of type 2 diabetes mellitus, cardiovascular disease and colon cancer. Metabolism, 2012. 61(8): p. 1058-1066.

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About the author

Prokopis Konstanti MSc performs PhD research in the group of Molecular Ecology at the Laboratory of Microbiology, Wageningen University (the Netherlands). He specializes in molecular analysis of microbial communities, and explores the role of microbes in human physiology focusing on the gut brain axis.

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