What are prebiotics and what is the difference to probiotics?

⏱ 12 min read

The importance of probiotics has long been recognized. These live bacteria have been shown to be beneficial in combating gastrointestinal problems and promoting healthy digestion. They also play an important role in strengthening the immune system.

Probiotics are found in the cultures of dairy products such as yoghurt. Their relatives - prebiotics - are less well known, although this is changing. In this article, you will learn about them and how they are related to probiotics, what they actually are, what they do and how they help your body. We'll also tell you about the many foods that contain prebiotics and what supplements you can take to get your daily healthy dose of prebiotics.

Probiotics vs prebiotics: what is the difference?

Probiotics are defined by the WHO and the Food and Agriculture Organization (FAO) as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host". In 2014, an expert panel of the International Scientific Association for Probiotics and Prebiotics (ISAPP) confirmed this definition (Hill et al., 2014). Most of the strains tested in studies are lactobacilli and bifidobacteria (Hempel et al., 2012).

Prebiotics have been defined by ISAPP since 2017 as "a substrate that is selectively utilized by host microorganisms conferring a health benefit". So prebiotics are not alive: they are food for your gut bacteria. A substance only counts as prebiotic if this health benefit has been shown (Gibson et al., 2017).

Synbiotics are mixtures of live microorganisms and a substrate that microorganisms use selectively, with a health benefit for the host (Swanson et al., 2020). One example is a probiotic powder with inulin.

Postbiotics are preparations of microorganisms that are no longer alive, or of their components, that benefit health. Unlike probiotics, the microorganisms in them are inactivated (Salminen et al., 2021).

How are probiotics and prebiotics related?

First of all, both probiotics and prebiotics fulfill important health functions for the human gut. Probiotics are live microorganisms that reach your gastrointestinal tract when you consume them. There they support a balanced gut flora and regular digestion. Like all living things, probiotics need food to stay active and healthy so you can have as much of them as possible.

This food is prebiotics. In other words: probiotics eat prebiotics. 

View the Bloat Relief Pack  ➜

Enzyme complex + probiotics + artichoke

How do you get prebiotics?

Put simply, prebiotics are certain fibers, or more precisely: plant fibers that your body cannot digest on its own. They reach the large intestine unchanged, where gut bacteria break them down. The best studied are fructans such as inulin and oligofructose, and galacto-oligosaccharides (So et al., 2018).

You are probably digesting prebiotics and don't even know it. This is because they are found in many of the foods you eat every day. Not every fiber is a prebiotic, but many fiber-rich plants also contain prebiotic fibers.

Which foods contain prebiotics?

Here you will find the most interesting representatives from the list of prebiotic foods. And you can ask yourself how many of them you want to include in your diet this week. 

Prebiotics in raw chicory (root chicory)

With almost 65% fiber, chicory (also known as common chicory) is one of the best sources of prebiotics available. You can find them in health food stores or markets, either processed into supplements or raw. You may have eaten them without realizing it, as chicory is added to some foods such as cereals, breakfast bars, milk products and bread.

You may also be familiar with the coffee-like taste, although chicory does not contain caffeine. Nevertheless, they have often been used as a coffee substitute (chicory coffee or "muckefuck"), which helps to avoid side effects such as jitteriness or insomnia, which some people suffer from if they drink too much coffee. 

Prebiotics statistics

Prebiotics in raw Jerusalem artichoke (Jerusalem artichoke)

You are probably familiar with the large, green, spherical artichoke that makes such delicious dips from your local greengrocer. But that's not what we mean; the Jerusalem artichoke is a completely different plant that has nothing to do with artichokes, except that it has a similar taste to the artichoke heart - which is why it is sometimes called that, although its real name is "Jerusalem artichoke". In fact, it looks more like ginger than artichokes; it is also known as (horse)earth apple or earth sunflower, as it is related to sunflowers. It is extremely rich in fiber and an excellent source of nutrients. Apart from its role as an excellent prebiotic, it also contains plenty of iron and potassium.

You can enjoy this prebiotic as a salad, boil it, sauté it or fry it like a roast potato. For the latter, the Jerusalem artichoke is a popular substitute for diabetics, as its glycemic index is very low. 

Prebiotics statistics

Prebiotics in dandelion leaves

Dandelion leaves are rich in valuable nutrients such as vitamin K, vitamin A, calcium and iron. In fact, one cup of raw dandelion leaves provides 535% of the recommended daily intake of vitamin K, which supports blood clotting and helps to maintain bone density, especially in older people.

You can enjoy the prebiotic benefits of raw dandelion leaves by adding them to salads or using them as an ingredient in sandwiches, stews, braised dishes, soups or herbal teas. As they taste a little bitter when raw, you can blanch them briefly in boiling water to soften the taste. 

Prebiotics statistics 

Prebiotics in raw garlic

Raw garlic is also rich in nutrients such as manganese, vitamin B6, vitamin C and selenium. There are several healthy ways to consume raw garlic - for example as a flavoring ingredient in 

• Guacamole,
• Hummus,
• Vegetable pans or
• Pasta dishes 

However, you should have plenty of mouthwash available... 

Prebiotics statistics 

Prebiotics in raw leeks

The good thing about leeks, apart from the fact that they are a high-quality prebiotic, is that they can be used with practically any dish. As a sweeter version of the onion, it is just as suitable for pasta as it is as an ingredient for garden salads or as a garnish for your quiche.

Of course, it is also perfect for soups - but when cooked, it loses a good part of its prebiotic ingredients. One cup of raw leek, including onion and stalk, contains no less than 52% of the recommended daily intake of vitamin K and 18% of vitamin C. 

Prebiotics statistics 

Prebiotics in raw onions

Like garlic, onions belong to the genus Allium, which used to be classified in the lily family. Eating raw onions provides you with organic sulphur compounds, but these are destroyed as soon as the onions are cooked.

In addition to sulphur - an important mineral for your body - raw onions also contain chromium, which contributes to the maintenance of normal blood glucose levels (Regulation (EU) No 432/2012), quercetin, which fights free radicals, and vitamin C. Since most of the valuable flavonoids are contained in the outer layers of the onion, you should peel off as few layers as possible before cutting or tearing the onion. If raw onions give you heartburn or indigestion, consider cooked onions, also a highly prebiotic food. 

Prebiotics statistics 

Prebiotics in cooked onions

As with raw onions, there are many ways to incorporate cooked onions into your daily diet. They can be caramelized, deep-fried, grilled or sautéed. But apart from that, many say the best way to enjoy cooked onions is with a hot bowl of French onion soup with creamy, melted provolone. 

Prebiotics statistics

Prebiotics in raw asparagus

Raw asparagus is another excellent source of prebiotics, as its fiber makes up 5% of the total weight. It may be difficult to eat raw due to its tough texture, so fermentation is a wonderful tasting alternative.

Raw asparagus also looks pretty good in a smoothie. 

Prebiotics statistics

Prebiotics in raw wheat bran

Wheat bran is also a good prebiotic, with the same fiber content as raw asparagus and cooked onions. You can add it to your breakfast cereals, mix it into your yogurt or use it as a smoothie ingredient.

Prebiotics statistics 

Prebiotics in roasted wheat flour

Toasted wheat flour produces a more flavorful, denser version of your favorite pastry. At 14 %, it also contains more protein than all-purpose wheat flour with a protein content of 11.7 %.

Prebiotics statistics

Prebiotics in raw bananas

Raw bananas are already packaged, so to speak, thanks to their peel and are therefore a practical source of prebiotics that you can take with you wherever you go. Simply peel them and eat them as a snack or while exercising! Bananas are also rich in potassium - one cup of the crushed fruit provides you with 23% of the recommended daily intake. 

Prebiotics statistics 

And what are probiotic food sources?

Fermented dairy products can contain live cultures, meaning microorganisms that are still active. The following fermented dairy products are widely used: 

• Yogurt
• Cheese
• Kefir
• Sour cream

Fermented does not automatically mean probiotic, though. ISAPP describes fermented foods as "foods made through desired microbial growth and enzymatic conversions of food components" and explicitly distinguishes them from probiotics (Marco et al., 2021). A product only counts as probiotic if its live microorganisms have shown a health benefit in adequate amounts (Hill et al., 2014). And if a food is heated or pasteurized after fermentation, its microorganisms are no longer alive.

What are the benefits of probiotics and prebiotics? What studies show

Antibiotics: In a pooled analysis of 63 controlled trials with 11,811 participants, probiotics were linked to a 42% lower risk of antibiotic-associated diarrhea (relative risk 0.58) (Hempel et al., 2012).

Constipation: In 14 trials with 1,182 adults with functional constipation, probiotics shortened gut transit time by an average of 12.4 hours and increased bowel movements by 1.3 per week. The effect was clearest for Bifidobacterium lactis (Dimidi et al., 2014).

Irritable bowel and bloating: An international expert group reviewed 70 studies and concluded that specific probiotics reduce overall symptoms and abdominal pain in some people with irritable bowel syndrome. With a moderate level of evidence, they also eased bloating and improved how often and how easily stools were passed (Hungin et al., 2018).

Gut flora: For prebiotics, the effect on gut bacteria is the best documented. In an analysis of 64 studies with 2,099 healthy adults, more dietary fiber led to more bifidobacteria and lactobacilli in the stool, especially with fructans such as inulin and with galacto-oligosaccharides (So et al., 2018). How the gut flora is linked to the brain is explained in our article on the gut-brain axis, and practical steps are covered in building up your intestinal flora.

View the Bloat Relief Pack  ➜

Enzyme complex + probiotics + artichoke

How do you use prebiotics? Raw or cooked?

As with most foods, the composition of prebiotics changes as soon as they are cooked. This means that they lose some of their valuable prebiotic fibers.

Exactly how much is lost is not known, but it's reasonably safe to assume that the less you heat them, the more healthy prebiotic fiber is retained. So instead of cooking dandelion leaves, just toss them into a salad and eat them raw. And if you absolutely must cook them, you can preserve more prebiotic fiber with careful steaming than by boiling or sautéing them.

How much prebiotics do you need?

There is no official recommended intake for prebiotics. A Western diet provides roughly 1 to 10 g of inulin and oligofructose a day, out of a recommended total fiber intake of around 25 g (van Loo et al., 1995). In a controlled trial with healthy adults, up to 10 g of inulin and up to 5 g of oligofructose a day were well tolerated; the most common complaints were flatulence and bloating (Bonnema et al., 2010). How much prebiotic fiber actually reaches your gut also depends on how the food is prepared. 

For example, it depends on whether you eat the food raw or cooked - and also on how you cook it. This has a significant influence on the prebiotic ingredients in your food. 

Are there food supplements with prebiotic fibers?

As the health benefits of prebiotics gain increasing attention, there are now a number of prebiotic supplements available to help you incorporate prebiotic fibers into your diet.

Should you take them? For many, the answer is simple: yes, you should.

Food supplements are the best way to accurately measure the amount of prebiotics in your diet because they contain predetermined, defined quantities. They are also available in practical powder form and can therefore be easily added to food.

So if you take a supplement with a fixed amount of prebiotics every day, you know exactly how much prebiotic fiber you are getting. It also makes it easy to adjust the amount and avoid unpleasant side effects such as bloating or discomfort, which can occur with too many prebiotics.

Prebiotics make your gut happy

Prebiotics are an essential part of a healthy diet - and they make your gut happy. If you want to make sure you're getting the real thing, it makes perfect sense to take a 100% natural supplement that has the full prebiotic spectrum. Only with such a supplement can you be sure that you are taking the right amount of pure and natural prebiotics.

What are the health benefits of prebiotics?

The sooner you start taking prebiotics regularly and in the right way, the sooner you may benefit from their possible health effects: 

• Improvement of calcium and magnesium absorption
• Stronger bones, increased bone density
• Improved and stronger immune system
• Reduced triglyceride levels in the blood
• Better weight control and a "healthy" appetite
• Most important: More healthy bacteria in the intestinal flora
• At the same time, fewer "bad" bacteria in the intestinal tract
• Reduced bacterial flow through openings in the intestinal wall in the course of so-called "leaky gut syndrome"
• More regular digestion
• Possible decrease in infections of the digestive tract
• Possible reduction of inflammation of the colon wall
• Possible reduction in anxiety 

The effect on the gut flora is the best documented: more prebiotic fiber, especially inulin and other fructans, led to more bifidobacteria and lactobacilli in studies (So et al., 2018). Mild flatulence can occur at first, so it is worth increasing the amount slowly.

Frequently asked questions

What is the difference between probiotics and prebiotics?

Probiotics are live microorganisms, mainly lactobacilli and bifidobacteria, that benefit your health in adequate amounts. Prebiotics are not alive: they are mostly fibers such as inulin that beneficial gut bacteria use as food. A product that contains both is called a synbiotic.

Should I take prebiotics and probiotics together?

Yes, the two can be combined without any problem, since prebiotics are food for beneficial gut bacteria. That is exactly the idea behind synbiotics, which contain live microorganisms together with a substrate such as inulin. You can also get both from your diet, for example yogurt with live cultures plus onions, leeks or garlic.

What happens when you start taking prebiotics and probiotics?

In the first days, some people notice mild flatulence or a bloated feeling, mainly from the prebiotic fibers. In a trial with healthy adults, up to 10 g of inulin and up to 5 g of oligofructose a day were well tolerated. Starting with a small amount and increasing it slowly makes the switch easier.

Can probiotics help with bloating?

Specific probiotics can: according to an international expert group, they reduce overall symptoms and abdominal pain in some people with irritable bowel syndrome and, with a moderate level of evidence, also ease bloating. The effect depends on the strain, so not every probiotic works the same way.

Are there side effects of probiotics?

Probiotics are considered safe for most people. Prebiotics can cause flatulence and bloating, especially at the start. Theoretical risks such as infections mainly concern particularly vulnerable people, so anyone with a severely weakened immune system should talk to their doctor before taking probiotics (Doron and Snydman, 2015).

Sources

Hill C, Guarner F, Reid G, Gibson GR, Merenstein DJ, Pot B, Morelli L, Canani RB, Flint HJ, Salminen S, Calder PC, Sanders ME (2014). Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nature Reviews Gastroenterology & Hepatology, 11(8):506–514. doi: 10.1038/nrgastro.2014.66

Gibson GR, Hutkins R, Sanders ME, Prescott SL, Reimer RA, Salminen SJ, Scott K, Stanton C, Swanson KS, Cani PD, Verbeke K, Reid G (2017). Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nature Reviews Gastroenterology & Hepatology, 14(8):491–502. doi: 10.1038/nrgastro.2017.75

Swanson KS, Gibson GR, Hutkins R, Reimer RA, Reid G, Verbeke K, Scott KP, Holscher HD, Azad MB, Delzenne NM, Sanders ME (2020). The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of synbiotics. Nature Reviews Gastroenterology & Hepatology, 17(11):687–701. doi: 10.1038/s41575-020-0344-2

Salminen S, Collado MC, Endo A, Hill C, Lebeer S, Quigley EMM, Sanders ME, Shamir R, Swann JR, Szajewska H, Vinderola G (2021). The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nature Reviews Gastroenterology & Hepatology, 18(9):649–667. doi: 10.1038/s41575-021-00440-6

Marco ML, Sanders ME, Gänzle M, Arrieta MC, Cotter PD, De Vuyst L, Hill C, Holzapfel W, Lebeer S, Merenstein D, Reid G, Wolfe BE, Hutkins R (2021). The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nature Reviews Gastroenterology & Hepatology, 18(3):196–208. doi: 10.1038/s41575-020-00390-5

Hempel S, Newberry SJ, Maher AR, Wang Z, Miles JN, Shanman R, Johnsen B, Shekelle PG (2012). Probiotics for the prevention and treatment of antibiotic-associated diarrhea: a systematic review and meta-analysis. JAMA, 307(18):1959–1969. doi: 10.1001/jama.2012.3507

Dimidi E, Christodoulides S, Fragkos KC, Scott SM, Whelan K (2014). The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials. The American Journal of Clinical Nutrition, 100(4):1075–1084. doi: 10.3945/ajcn.114.089151

Hungin APS, Mitchell CR, Whorwell P, Mulligan C, Cole O, Agréus L, Fracasso P, Lionis C, Mendive J, Philippart de Foy JM, Seifert B, Wensaas KA, Winchester C, de Wit N (2018). Systematic review: probiotics in the management of lower gastrointestinal symptoms – an updated evidence-based international consensus. Alimentary Pharmacology & Therapeutics, 47(8):1054–1070. doi: 10.1111/apt.14539

So D, Whelan K, Rossi M, Morrison M, Holtmann G, Kelly JT, Shanahan ER, Staudacher HM, Campbell KL (2018). Dietary fiber intervention on gut microbiota composition in healthy adults: a systematic review and meta-analysis. The American Journal of Clinical Nutrition, 107(6):965–983. doi: 10.1093/ajcn/nqy041

van Loo J, Coussement P, de Leenheer L, Hoebregs H, Smits G (1995). On the presence of inulin and oligofructose as natural ingredients in the western diet. Critical Reviews in Food Science and Nutrition, 35(6):525–552. doi: 10.1080/10408399509527714

Bonnema AL, Kolberg LW, Thomas W, Slavin JL (2010). Gastrointestinal tolerance of chicory inulin products. Journal of the American Dietetic Association, 110(6):865–868. doi: 10.1016/j.jada.2010.03.025

Doron S, Snydman DR (2015). Risk and safety of probiotics. Clinical Infectious Diseases, 60(Suppl 2):S129–S134. doi: 10.1093/cid/civ085

Commission Regulation (EU) No 432/2012 of 16 May 2012. Establishing a list of permitted health claims made on foods, other than those referring to the reduction of disease risk and to children's development and health. Official Journal of the European Union, L 136:1–40.