Prebiotic Types
GPA recognizes the below categories as established and/or emerging types of prebiotics.
Please click below to access detailed guides for each type. We continuously monitore the science surrounding prebiotics and these type guides are updated as new science emerges.
Acacia fiber is a non-viscous, fermentable dietary fiber that is obtained from the branches of Acacia senegal and A. seyal trees as a water-soluble exudate (Al-Jubori et al., 2023). It is an arabinogalactan-protein complex containing macro-polysaccharides, a small amount of protein, traces of phytoconstituents such as flavonoids, saponins, polyphenolic tannins, and others, and salts of Arabic acid with calcium, magnesium, and potassium (Ashour et al., 2022). Acacia fiber is nondigestible in the human body but fermentable by the large intestine’s microbiota, consequently modulating the resident taxa, specifically bifidobacteria and lactobacilli, and producing short-chain fatty acids (SCFAs) (Calame et al., 2008; Cherbut et al., 2003; Daguet et al., 2015).
Acacia fiber is among the oldest and most well-known natural gums, with its usage dating back 5,000 years (Patel & Goyal, 2015). Today, acacia fiber is a functional ingredient used in human food, animal feed, and various other industries.
Fructooligosaccharides (FOS) is a type of oligosaccharide defined as nondigestible carbohydrates consisting of glucose and fructose sugar molecules connected by β (21) glycosidic bonds and a degree of polymerization that varies from 2 to 60 chain lengths (Kaur et al., 2021; Kherade et al., 2021). FOS is commonly referred to as oligofructose, oligofructan, fructose oligomers, fructans, and glycofructans, and is regularly incorporated into various food applications and wellness products due to its functional properties and extensive health benefits (Kherade et al., 2021). FOS can be found in approximately 36,000 different plants, cereals, and honey; however, these sources only provide trace amounts of FOS, resulting in the need for commercial production (Davani-Davari et al., 2019; Dou et al., 2022; Kherade et al., 2021).
Galactooligosaccharides (GOS) has been recognized as a prebiotic for over two decades as its prebiotic activity has been extensively demonstrated in in vitro and in vivo animal and human studies.
GOS is composed of linear and branched oligosaccharides with two to eight degrees of polymerization (Wang et al., 2023). It is an indigestible food component that passes through the stomach and small intestine intact to reach the colon where it gets fermented by the gut microbiota. GOS further modulates the gut microbiota, increasing the abundance and enhancing the functionality of beneficial bacteria and conferring health benefits beyond the gut to various bodily systems (Azcarate-Peril et al., 2021; Mei et al., 2022; Wang et al., 2023).
Guar gum is an edible fibre derived from Cyamopsis tetragonolobus seeds, a leguminous plant cultivated primarily in India and Pakistan (Awan et al., 2024; Mudgil et al., 2014). The seeds of the guar plant are comprised of galactomannan, linear polysaccharides consisting of a mannose backbone and galactose side chains, responsible for guar gum’s thickening, emulsifying, and stabilizing properties (Awan et al., 2024; Mudgil et al., 2014; Thombare et al., 2016). Partially hydrolyzed guar gum (PHGG) is a water-soluble dietary fibre made from guar gum that has undergone partial enzymatic hydrolyzation, via microbial endo-β-mannanase, converting it to a low viscosity polysaccharide (Mudgil, 2018). PHGG moves through the upper gastrointestinal tract undigested and is fermented by colonic bacteria, resulting in the production of short-chain fatty acids (SCFA), such as butyrate, attributing PHGG’s use as a prebiotic (Sakai et al., 2022).
Human breast milk is primarily comprised of lactose, lipids, and HMOs. The composition of HMOs varies from person-to-person, based on genetic and environmental factors such as ethnicity, geographical location, lactation stage, infant age, and maternal health, age, and nutrition (Corona et al., 2021).
A further breakdown of HMOs illustrates that they are complex, unconjugated glycans naturally and abundantly found in human milk at concentrations ranging from 20 – 24 g/L in early milk (i.e., colostrum) to 10 – 15 g/L in more mature milk (Triantis et al., 2018; Zhang et al., 2021). There are over 200 known HMO structures that uniquely consist of five simple sugars (D-glucose, D-galactose, L-fucose, N-acetyl-D-glucosamine (GlcNAc), and N-acetylneuraminic acid (Neu5A)), and new HMO structures are continually being identified with the ongoing advancement of analytical methods (Palur et al., 2023). These indigestible oligosaccharides are responsible for providing prebiotic, immunological, anti-pathogen, as well as gut and intestinal health properties; therefore, human milk is considered the gold standard of infant nutrition by the World Health Organization (Palur et al., 2023; Zhang et al., 2021).
With breastfeeding rates on a global decline and an enhanced public interest in prebiotic supplementation, the development of HMOs for formula, food, and other health applications is an exciting opportunity to take advantage of these unique sugars and their wellness properties.
Inulin is a naturally occurring, water-soluble, storage polysaccharide that belongs to a group of non-digestible carbohydrates called fructans (Shoaib et al., 2016; Teferra, 2021). The structural composition of inulin consists of linear D-fructose units with β (21) linkages and one terminal glucose molecule with α (12) linkage (Ahmed & Rashid, 2019; Teferra, 2021; Perinelli, 2023). Inulin is innately found in over 36,000 plant species; however, it is primarily abundant in chicory root, dahlia, and Jerusalem artichoke (Niness, 1999; Shoaib et al., 2016; Gupta et al., 2019).
Widely used as a prebiotic, fat and sugar replacer, and food texture modifier, inulin is often used in the development of functional foods due to its health benefits and technical properties (Shoaib et al., 2016). In the human body, inulin is not readily digested, fermented, or absorbed in the initial gastrointestinal tract, but is instead digested in the distal portion of the colon by pulling in water, managing constipation, and promoting the growth of colonic microbiota (Shoaib et al., 2016; Gupta et al., 2019). These properties make inulin a soluble dietary fiber and efficient prebiotic.
Isomaltooligosaccharides (IMOs) are low-degree polysaccharides with at least one α-(1→6) glycosidic bond between glucose residues and a monosaccharide number of 2-5 (Chen et al., 2022). They are found naturally in soy sauce, sake, rice miso, honey, and fermented foods such as kimchi and sourdough bread and commercially from starch-derived sources (Palaniappan and Emmambux, 2023). IMOs are partially digested in the human body by brush border enzymes, including maltase/glucoamylase and isomaltase, while the undigested oligosaccharides get fermented in the large intestines, leading to beneficial gastrointestinal effects and prebiotic properties (Chen et al., 2022).
Lactulose is a synthetic, non-digestible, disaccharide that is derived from the chemical or enzymatic isomerization of lactose using β-galactosidase or epimerase (Sitanggang et al., 2016; Karakan et al., 2021; Chu et al., 2022). Lactulose is comprised of two sugar molecules, fructose and galactose, bonded together with a β-1-4-glycosidic bond, making it indigestible in the mammalian gastrointestinal tract (Panesar & Kumari, 2011).
Lactulose provides several prebiotic functions such as improving gut health, increasing the production of beneficial metabolites, and increasing mineral absorption. Once lactulose reaches the colon intact, it is metabolized, stimulating the growth of healthy bacteria, and inhibiting the growth of pathogens (Panesar & Kumari, 2011). Lactulose is commonly used in many food and pharmaceutical applications.
The technical properties of lactulose make it a useful ingredient for food purposes such as a sweetening agent, fermentable carbohydrate, or thickening agent, and it has also been reported to improve the survival of probiotic strains in yogurt (Panesar & Kumari, 2011). The health benefits of lactulose have been extensively demonstrated through various clinical trials and pharmaceutical applications. Lactulose is regulated as a prescription drug in many countries, including the United States (US).
Polyphenols are a large class of plant-based organic compounds with one or more phenolic rings bearing hydroxyl groups in their chemical structure (Lippolis et al., 2023). Polyphenols constitute the fourth major ingredient in plants behind cellulose, hemicellulose, and lignin (Chen et al., 2022), with more than 8,000 phenolic compounds identified to date. Many of these phenolic compounds have complex chemical structures, contributing to their various biological functions (Lippolis et al., 2023). One of polyphenols’ many biological functions is their prebiotic activity through gut microbiome modulation, which then translates to numerous health benefits in the host (Li et al., 2023a; Lippolis et al., 2023).
Resistant Starch (RS) is an insoluble type of dietary fiber that is resistant to digestion by α-amylase and pullulanase enzymes in the small intestine and may be fermented by the colon microbiota, producing carbon dioxide, hydrogen, methane, and short-chain fatty acids (SCFAs) (Bojarczuk et al., 2022; Tekin & Dincer, 2023).
Before the rise of processed foods, RS was a primary dietary feature worldwide and people routinely consumed 30 to 40 g of RS per day (Stephen et al., 1995; O’Keefe et al., 2015). Food processing has converted most of the RS in our diet into high glycemic, easily digestible starch, reducing the total amount consumed (Ashwar et al., 2016; Birt et al., 2013). Males and females in the United States (US) only consume about 4.6 g and 3.3 g of RS per day, respectively (Miketinas et al., 2020), while individuals following Ketogenic or Paleolithic diets may consume even less (Genoni et al., 2019). With lower consumption, the metabolic consequences of less dietary RS are now becoming known, including microbiome dysbiosis, manifested in a depletion of the keystone species Bifidobacterium (Ang et al., 2020), and various other health disruptions.
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Resistant dextrin (RD) is a glucose polysaccharide produced from corn, maize, wheat, or other edible starch through a heating and enzymatic treatment. During dextrinization, starch is degraded under the action of acid and heat, and new bonds, including β-1,6, β-1,2, α-1,6, and α-1,2 bonds are formed (Zhen et al., 2021). Only 15% of RD is enzymatically digested by the small intestine, meanwhile 75% reaches the colon and is slowly fermented, and the remaining 10% is excreted in the feces (Shamasbi et al., 2019).
RD is often added to various food products, including beverages and baked goods to increase fiber content without significantly altering taste or texture. The RD used in a study by Aliasgharzadeh et al. (2014), NUTRIOSE® 06, is a purified RD glucose polymer (rich in α-1,4 and α-1,6 linkages) derived from wheat (NUTRIOSE®FB06) or maize (NUTRIOSE®FM06), which has shown to induce metabolic and health benefits via selective modulation of the human gut microflora. Specifically, RD is shown to modulate the gut microbiota by increasing Bacteroides species, decrease Clostridium perfringens, and produce several short chain fatty acids (SCFAs) (Thirion et al., 2022). RD additionally demonstrates protective effects on inflammation-induced disruptions of the intestinal barrier, thought to be due to increased acetate and propionate levels, and overall enrichment of SCFA-producing bacteria (Perreau et al., 2023).
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Tagatose is a naturally occurring monosaccharide having sweetness 90% that of sucrose (Roy et al., 2018). Tagatose is a stereoisomer of fructose, only differing at the fourth carbon atom, and is naturally found in a variety of fruits and dairy products. Tagatose can be produced for the commercial market using lactose, fructose or maltodextrin as feedstocks as well as by enzymatic conversion of starches (Bertelsen et al., 1999; Food Safety Authority Ireland, 2017; Bonumose LLC, 2020).
Tagatose is a bulk sweetener with no odor or off-flavors. It is a white crystalline powder that takes part in the Maillard reaction, which leads to the browning of food. Only 15-20% of D-tagatose is absorbed in the small intestine, leaving the remaining 80-85% of ingested D-tagatose to be fermented in the colon by indigenous microflora, leading to various prebiotic effects and a reduced caloric value compared to traditional sugars (Bertelsen et al., 1999). In-vitro studies have demonstrated that tagatose as a synbiotic substrate enhances the growth of Lactobacillus casei 01 and Lactobacillus rhamnosus strain GG, reinforcing the attachment on epithelial cells, and therefore enhancing cholesterol-lowering activities (Koh et al., 2013).
The whole food matrix refers to the complex and synergistic interactions between the natural components of whole foods, including nutrients, minerals, bioactive compounds, food structures, and others (e.g., phospholipids, prebiotics, and probiotics) (Mozaffarian, 2019). These interactions involve chemical and physical processes that affect the release, mass transfer, accessibility, digestibility, and stability of the food components, consequently influencing how these components are utilized by the body to impact health and disease (Aguilera, 2019).
Advances in nutrition science have revealed the importance of consuming a variety of whole foods compared to focusing on individual nutrients; as such, stepping away from the old approach commonly adopted in the 20th century, known as the reductionist approach (Mozaffarian, 2019). Ingestion of whole foods not only offers an additive benefit of the individual components, but consuming foods in their natural forms can also enhance nutrient absorption and bioavailability in most cases.
Xylooligosaccharides (XOS) is a functional oligosaccharide that has gained widespread attention in recent years from both scholars and industry for its prebiotic activity (Yan et al., 2022). XOS is a mixture of oligosaccharides containing β-1,4-linked xylose residues, naturally occurring in bamboo shoots, fruits, vegetables, milk, and honey (Divyashri et al., 2021). In the body, XOS gets fermented by Bifidobacterium spp. and Lactobacillus spp. in the microbiota, consequently increasing their relative abundance within the gastrointestinal tract and producing fecal short-chain fatty acids (SCFAs) (Lin et al., 2016).