Prebiotics

What are they, and how can they help you?

Prebiotics are defined as “a substrate that is selectively utilized by host microorganisms conferring a health benefit” [ISAPP, IPA, 2025]

This page is intended to be a resource for health care professionals and consumers looking for scientifically-backed information regarding prebiotics, including types of prebiotics and their applications.

How Prebiotics Work

Prebiotics have many physiological effects within the digestive tract and throughout the body

Different physiological effects will be observed depending upon the specific prebiotic that is consumed

Stimulate growth of beneficial bacteria

Prebiotics selectively stimulate the growth and activity of beneficial bacteria, e.g. Bifidobacteria and Lactobacilli in the colon and elsewhere in the body.

Produce short-chain fatty acids (SCFAs)

SCFAs include acetic acid, propionic acid, and butyric acid. These beneficial metabolites are produced when prebiotics are used by beneficial gut bacteria. SCFAs support the health of your colon, and help to regulate cholesterol and blood glucose.

Support the immune system

Fermentation of prebiotics by beneficial bacteria can produce metabolites that affect the immune system. These metabolites can also influence the development and response of immune cells. This supports immune health.

Enhance mineral absorption

Some prebiotics enhance the absorption of certain minerals, e.g. calcium and magnesium, within the colon. This occurs because of changes in intestinal pH caused by SCFAs. Increased calcium and magnesium absorption supports bone health and the cardiovascular system.

Reduce inflammation

The beneficial bacteria resulting from prebiotic consumption can support the mucosal layer in the digestive tract.

This enhancement of gut barrier function can reduce inflammation within the gut and elsewhere in the body

Acidification within the colon

Prebiotic fermentation by beneficial gut bacteria produces SCFAs that reduce colonic pH.

This limits growth of certain pathogenic bacteria, and reduces protein fermentation

Home

Types of Prebiotics

The following prebiotics are scientifically recognized to provide physiological benefits

Acacia

Also known as gum arabic, acacia is a complex mixture of polysaccharides (mainly arabinose and galactose), some of which are bound to proteins. The primary source is a tree gum extracted from Acacia sensu latu trees and shrubs. It is not as widely studied as other prebiotics, and may have benefits as a fiber if high molecular weight forms are consumed.

More Details

Arabinoxylo-oligosaccharides (AXOS)

Arabinoxylo-oligosaccharides are longer chain oligosaccharides mainly containing xylose subunits, with some arabinose subunits connected to the xylose. AXOS is usually produced by hot water extraction of the arabinoxylan found in the bran within wheat , barley, and other grains.

More Details

Beta-glucan (solubilized)

Solubilized/hydrolyzed beta-glucan can be extracted from cereals such as wheat, oats, and barley, among other plant sources. It is important to note that beta-glucan that has not been hydrolyzed is not particularly effective as a prebiotic (structure is too complex for fermentation), although it is still valuable as a fiber source.

More Details

Fructo-oligosaccharides (FOS)

Fructo-oligosaccharides exist in two forms - those produced by hydrolysis of inulin (so-called long chain or FFn-FOS), and those produced by enzymatic combination of fructose with sucrose (so-called short-chain FOS, or GFn-FOS). FFn-FOS is naturally found in low quantities in foods such as bread, garlic, and onions

More Details

Galacto-oligosaccharides (GOS)

Galacto-oligosaccharides are naturally found in certain legumes (e.g., beans, chickpeas) and breast milk. GOS is also commonly produced by an enzymatic reaction using lactose and galactose, usually using whey permeate from cheese processing. GOS usually includes 4 - 6 carbohydrate sub-units.

More Details

Human Milk Oligosaccharides (HMOS)

HMOS are a family of complex carbohydrate (sugar) molecules naturally found in breast milk. They have lactose as their primary structural component, and contain at least one of four other monosaccharides (N-acetyl-D-glucosamine, L-fucose , D-galactose, and/or sialic acid) connected to lactose. Examples include 2'-fucosyllactose and 3'-sialyllactose.

Some of these complex HMOS molecules are also being produced synthetically using enzymes or precision fermentation, using lactose as the primary starting material.

More Details

Inulin

Inulin is a polymer of fructose, found naturally in plants such as Jerusalem artichokes, agave, and the roots of chicory plants. Inulin is also found in low amounts in asparagus, onions, bread, and bananas. The inulin found is supplements is mainly extracted from chicory root or agave. If inulin is hydrolyzed with enzymes, long chain fructo-oligosaccharides (FFn-FOS) can be produced.

More Details

Isomalto-oligosaccharides (IMOS)

Isomalto-oligosaccharides are glucose oligomers. They differ from starch (another glucose polymer) because they have α-D-(1,6)-bonds, which make them resistant to break down by amylase in the digestive tract. Examples of IMOS include isomaltose, panose, isomaltotriose, isomaltotetraose, and isomaltopentaose.

More Details

Mannan-oligosaccharides (MOS)

Mannan-oligosaccharides (also known as manno-oligosaccharides) are chains of mannose, produced by breaking down mannan, a natural fiber found in plants such as coconut, palm kernels, coffee, and softwoods, and in the cell walls of yeast. MOS is typically produced using enzymes, and less commonly, by extraction using hot water. Note that many yeast products, although labelled as MOS, are technically mannan, bound to beta-glucan and protein. A true MOS prebiotic can be easily dissolved in water.

More Details

Pectin-oligosaccharides (POS)

Pectin-oligosaccharides (also known as pectic-oligosaccharides) are produced from pectin in fruits, vegetables and other plants, using enzymes or by hot water extraction. POS is made up of multiple units of the glucuronic acid and galacturonic acid found in the pectin fraction of fruits and other plants. The structures of POS tend to be complex with different side groups that depend upon the source of the pectin. POS thus represents a diverse but related family of compounds.

More Details

Resistant Starch

Resistant starch is a form of starch that is resistant to break down by amylases (digestive enzymes found in the mouth and digestive tract). There are multiple types of resistant starch. Some resistant starch is naturally found in potatoes and green (not yellow) bananas. Resistant starch can also be produced by cooking starchy foods like potatoes, rice, tapioca, or corn, and then allowing them to cool. The so-called retrogradation process during cooling causes the starch to become "resistant".

More Details

Xylo-oligosaccharides (XOS)

Xylo-oligosaccharides are chains of xylose, produced by breaking down xylan, a natural fiber found in plants such as corn cobs, wheat and barley straw, and sugar cane stalks. XOS (pronounced "zos") can be produced using hot water extraction, or using enzymes.

More Details

Home

Myths and Misconceptions

There are various myths and misconceptions regarding prebiotics

Learn more by checking out the information below, adapted from Saville et al., Beneficial Microbes, 16(1), 1-33. https://doi.org/10.1163/18762891-bja00056

All prebiotics are the same

FACT: All prebiotics are different. They have different structures, which affects the ability of certain microbes to utilize the prebiotic for fermentation. This leads to differences in dose, and different physiological impacts. Consumers should not just look for a prebiotic – they should look for the specific prebiotic compound that is best suited to them, and the physiological benefit that they are seeking.

All prebiotics are fiber, and all fibers are prebiotics

FACT: Most fibers are not directly fermentable because they are complex, insoluble structures. Few fibers meet the criteria to be classified as prebiotic compounds, although they have many other important health benefits.

FACT: Fiber is a regulatory definition, and very few prebiotic compounds meet the regulatory requirements for fiber.

Just get your prebiotics from food

FACT: Foods typically have low amounts of prebiotics, and it is very difficult to consume the required amount of prebiotic (from food) for a health benefit. For example, you would need to consume an entire loaf of bread, 1 – 2 kg of onions, or 15 (green) bananas every day to reach the recommended intake for fructans (based on the measured fructan content in foods, published by Moshfegh, 1999). Furthermore, many important prebiotics such as XOS, AXOS, HMOS and MOS cannot be found in food.

Most people will need supplements to complement their prebiotic intake from food and achieve the desired physiological benefit associated with that prebiotic.

Prebiotics only support digestive health

FACT: Prebiotics support digestive health by promoting the growth of beneficial bacteria; however, their benefits are not limited strictly to the digestive system. Research has shown that prebiotics can also have beneficial effects on various aspects of health, including immune function, mental health and weight management (Slavin, 2013; Delzenne, 2011; Cryan, 2012, Saville. 2020).

Prebiotics work immediately

FACT: It takes some time for the microbial community to adjust to the presence of a prebiotic compound. These changes may take several weeks before the resulting physiological benefits are observed.

Prebiotics are only food for probiotics

FACT: Prebiotics promote the growth of certain probiotics AND support the growth of beneficial microbes that are naturally present in the digestive tract. They help to create an environment in the digestive system that supports these beneficial microbes (Slavin, 2013; Gibson and Roberfroid, 1995; Holscher, 2017).

Prebiotics always cause digestive symptoms (gas, bloating, abdominal discomfort)

FACT: Several studies have demonstrated that prebiotics improve digestive health without adverse symptoms. Nonetheless, some individuals may experience mild digestive symptoms, including gas and mild bloating, when they start taking certain prebiotics. Gas and bloating may occur as the gut microbiota adjust to the addition of prebiotics to their intake (Holscher, 2017; Roberfroid and Gibson, 2010; Slavin, 2013). People that experience symptoms should start with a lower dose of the prebiotic, and gradually increase the dose to improve tolerance. Alternatively, a different prebiotic could be consumed that can provide a similar expected benefit without digestive issues.

More prebiotics (i.e. a higher dose) is better

FACT: The dose of a prebiotic needed depends on the type of the prebiotic and the desired physiological benefit. Certain prebiotics, such as XOS, require a much lower dose than other prebiotics, such as inulin. The dose required for e.g., improved laxation may differ from that needed to enhance mineral absorption and support bone health.

Consumers should only consume the appropriate dose based on the desired physiological benefit, supported by scientific research (Mysonheimer and Holscher, 2022; Gibson et al., 2010; Whelan, 2013; Halmos, 2015; Saville, 2018). Excessive doses could lead to issues with tolerance.

Home

Criteria

How Scientists Determine if a Compound is a Prebiotic

The criteria shown at right listed are the basis for the scientifically-accepted definition for a prebiotic (Saville et al., 2025; ISAPP).

The well-documented health benefits of prebiotics that meet these criteria have been the subject of rigorous research and clinical trials.

These criteria specifically apply to prebiotics used in the digestive tract. Some prebiotics may be used orally or topically, and therefore, criteria related to host digestion and absorption from the digestive tract would not apply.

Home

References

Cryan, J.F. and Dinan, T.G., 2012. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nature Reviews Neuroscience 13: 701-712. https://doi.org/10.1038/nrn3346

Delzenne, N.M. and Cani, P.D., 2011. A place for dietary fibre in the management of the metabolic syndrome. Current Opinion in Clinical Nutrition and Metabolic Care 14: 582-587. https://doi.org/10.1097/01.mco.0000171124.06408.71

Gibson, G.R., Scott, K.P., Rastall, R.A., Tuohy, K.M., Hotchkiss, A.T., Dubert-Ferrandon, A., Gareau, M.G., Murphy, E.F., Saulnier, D., Loh, G., Macfarlane, S., Delzenne, N.M., Ringel, Y., Kozianowski, G., Dickmann, R.S., Lenoir-Wijnkoop, I., Walker, C. and Buddington, R.K., 2010. Dietary prebiotics: current status and new definition. Food Science and Technology Bulletin: Functional Foods 7: 1-19. https://doi.org/10.1616/1476-2137.15880

Gibson, G.R., Hutkins, R., Sanders, M.E., Prescott, S.L., Reimer, R.A., Salminen, S.J., Scott, K., Stanton, C., Swanson, K.S., Cani, P.D., Verneke, K. and 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 and Hepatology14: 491-502. https://doi.org/10.1038/nrgastro.2017.75

Halmos, E.P., Christophersen, C.T., Bird, A.R., Shepherd, S.J., Gibson, P.R. and Muir, J.G., 2015. Diets that differ in their FODMAP content alter the colonic luminal microenvironment. Gut 64: 93-100. https://doi.org/10.1136/gutjnl-2014-307264

Holscher, H.D., 2017. Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes8: 172-184. https://doi.org/10.1080/19490976.2017.1290756

International Probiotics Association, 2025. https://ipa-biotics.org/wp-content/uploads/Press-release-IPA-Prebiotic-Definition-2025-05-27-final-2.pdf

International Scientific Association for Probiotics and Prebiotics (ISAPP), 2025. https://isappscience.org/for-consumers/learn/prebiotics/

Moshfegh, A.J., Friday, J.E., Goldman, J.P. and Ahuja, J.K., 1999. Presence of inulin and oligofructose in the diets of Americans. Journal of Nutrition 129(Suppl 7): 1407S-1411S. https://doi.org/10.1093/jn/129.7.1407S

Mysonhimer, A.R. and Holscher, H.D., 2022. Gastrointestinal Effects and Tolerance of Nondigestible Carbohydrate Consumption. Advances in Nutrition 13: 2237-2276. https://doi.org/10.1093/advances/nmac094

Roberfroid, M., Gibson, G.R., Hoyles, L., McCartney, A.L., Rastall, R., Rowland, I., Wolvers, D., Watzl, B., Szajewska, H., Stahl, B., Guarner, F., Respondek, F., Whelan, K., Coxam, V., Davicco, M.-J., Leotoing, L., Wittrant, Y., Delzenne, N.M., Cani, P.D., Nevrinck, A.M. and Meheust, A., 2010. Prebiotic effects: metabolic and health benefits. British Journal of Nutrition 104(Suppl 2): S1-S63. https://doi.org/10.1017/S0007114510003363

Saville, B.A. and Saville, S., 2018. Xylooligosaccharides and arabinoxylanoligosaccharides and their application as prebiotics. Applied Food Biotechnology 5: 121-130. https://doi.org/10.22037/afb.v5i3.20212

Saville, B.A. and Saville, S., 2020. Functional attributes and health benefits of novel prebiotic oligosaccharides derived from xylan, arabinan and mannan. In: Franco-Robles, E. and Ramı́rez-Emiliano, J. (eds.) Prebiotics and Probiotics – Potential Benefits in Nutrition and Health. IntechOpen, London, UK. https://doi.org/10.5772/intechopen.89484

Saville, S.H., Younes, J.A., Paraskevakos, G., & Venema, K. (2025). The prebiotic landscape: history, health and physiological benefits, and regulatory challenges – an IPA perspective part 1. Beneficial Microbes, 16(1), 1-33. https://doi.org/10.1163/18762891-bja00056

Slavin, J., 2013. Fiber and prebiotics: mechanisms and health benefits. Nutrients 5: 1417-1435. https://doi.org/10.3390/nu5041417.

Whelan, K. and Quigley, E.M., 2013. Probiotics in the management of irritable bowel syndrome and inflammatory bowel disease. Current Opinion in Gastroenterology 29: 184-189. https://doi.org/10.1097/MOG.0b013e32835d7bba