Inulin

Last Updated: November 2, 2023

Inulin is a type of soluble fiber that can be taken as a supplement or found naturally in foods (e.g., Jerusalem artichokes, chicory, asparagus, garlic, onions, wheat, bananas). Inulin can have prebiotic effects on the gut microbiome, leading to increases in the abundance of potentially beneficial bacteria, such as Bifidobacterium spp.. Inulin may have various benefits on gut health and overall health, but clinical trials tend to report inconsistent results, which may be due to variability in baseline microbiomes, habitual diets, and health status.

Inulin is most often used for

What is inulin?

Inulin is a fructan carbohydrate (i.e., a chain of fructose molecules) and soluble dietary fiber found naturally in some plants as a form of energy storage. While inulin can be taken as a supplement, it can also be consumed as part of the diet with foods such as Jerusalem artichokes, chicory, asparagus, garlic, onions, wheat, and bananas.[1] Structurally, inulin is usually composed of a straight chain of fructose sugars that are connected by a type of bond (a β-(2,1)-glycosidic bond) that is resistant to human digestive enzymes.[2] Because of this, inulin travels to the large intestine largely undigested and acts as a food source for microbes of the gut microbiome — primarily via bacterial fermentation. This process leads to the production of compounds capable of influencing human health — such as short-chain fatty acid (SCFAs), while also stimulating the growth of potentially beneficial bacteria.[3]

Inulin can be categorized based on the length of its fructose chain, which also influences its physiochemical properties (e.g., solubility, fermentation rate).[1] Long-chain inulin generally consists of 10 to 60 fructose units, while short-chain inulin has 2 to 10 fructose units and is referred to as a fructooligosaccharide (FOS) or oligofructose.[1] Together, short- and long-chain inulin are called “inulin-type fructans,” which will be used synonymously with “inulin” on this page.[4]

What are inulin’s main benefits?

Inulin is best known for its prebiotic effects on the gut microbiome, stimulating the growth of bacteria generally thought to be beneficial for health. Most consistently, inulin has been found to increase the absolute abundance of Bifidobacterium species. It may also increase levels of Lactobacillus species and Faecalibacterium prausnitzii, and decrease levels of Clostridium species (some of which are potentially pathogenic), although these effects are less consistently found.[3][5]

Regular supplementation with inulin may improve blood sugar regulation in people with type 2 diabetes or prediabetes),[2][6] reduce LDL cholesterol,[7] increase satiety,[3] improve bowel movement frequency and consistency,[8][9] increase the absorption of calcium and magnesium,[3] and, in people with overweight or obesity, reduce C-reactive protein.[10] While these are the effects most consistently observed in clinical trials, there is still a substantial amount of variability between studies, and the effects tend to be small in magnitude.

What are inulin’s main drawbacks?

Inulin is generally considered safe, and the main side effects are gastrointestinal in nature due to the gas produced during bacterial fermentation. Possible side effects include flatulence, abdominal rumbling or cramping, bloating, and diarrhea.[3][11] These side effects may be worse at higher doses and with short-chain inulin (oligofructose, FOS) due to faster fermentation rates.[11] Starting at a lower dose and increasing slowly over time can help to improve tolerance.[3]

One major limitation of inulin is how variable its effect can be between individuals. Many of the potential benefits of inulin are due to its interactions with the gut microbiome, but the microbes in the gut can vary greatly between different people, which could lead to inconsistent and unpredictable effects.[3] A study in mice found that after six months of consuming a high-fat diet (intending to mimic a Western diet) enriched with inulin, most mice developed liver damage and liver cancer, which seemed to be related to the production of secondary bile acids by certain gut bacteria. The authors suggested that the health effects (both positive and negative) of fermentable fibers may depend on the unique gut microbial environment. Importantly, the amount of inulin consumed daily in this study was not clear, and this negative effect has not been observed in human clinical trials.[12]

How does inulin work?

Most research suggests that inulin works primarily as a fermentable fiber which can undergo bacterial fermentation in the gut, leading to changes in the composition and function of the gut microbiome and the production of bioactive metabolites, like SCFAs.[3] SCFAs are capable of influencing the health of our body in a multitude of ways, including by promoting a healthy gut environment and helping to regulate appetite, inflammation, and metabolism.[4] While some clinical trials have reported increased levels of SCFAs in the blood or feces with inulin supplementation, most have actually failed to find an effect.[3] Additionally, while inulin can certainly modulate the gut microbiome, connecting these changes to beneficial health outcomes in humans has proved challenging. Ultimately, further research is needed to better understand how inulin works.

Examine Database: Inulin
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Update History
2023-11-02 00:30:03

A few new meta-analyses added

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We found a few more meta-analyses on inulin that we added to our database.

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References
  1. ^Qin YQ, Wang LY, Yang XY, Xu YJ, Fan G, Fan YG, Ren JN, An Q, Li XInulin: properties and health benefits.Food Funct.(2023-Apr-03)
  2. ^Rao M, Gao C, Xu L, Jiang L, Zhu J, Chen G, Law BYK, Xu YEffect of Inulin-Type Carbohydrates on Insulin Resistance in Patients with Type 2 Diabetes and Obesity: A Systematic Review and Meta-Analysis.J Diabetes Res.(2019)
  3. ^Hughes RL, Alvarado DA, Swanson KS, Holscher HDThe Prebiotic Potential of Inulin-Type Fructans: A Systematic Review.Adv Nutr.(2022-Mar)
  4. ^Sheng W, Ji G, Zhang LImmunomodulatory effects of inulin and its intestinal metabolites.Front Immunol.(2023)
  5. ^Ribeiro MC, Levi Y, Moraschini V, Messora MR, Furlaneto FACEffects of Prebiotic Therapy on Gastrointestinal Microbiome of Individuals with Different Inflammatory Conditions: A Systematic Review of Randomized Controlled Trials.Probiotics Antimicrob Proteins.(2023-Apr-24)
  6. ^Wang L, Yang H, Huang H, Zhang C, Zuo HX, Xu P, Niu YM, Wu SSInulin-type fructans supplementation improves glycemic control for the prediabetes and type 2 diabetes populations: results from a GRADE-assessed systematic review and dose-response meta-analysis of 33 randomized controlled trials.J Transl Med.(2019-Dec-05)
  7. ^Liu F, Prabhakar M, Ju J, Long H, Zhou HWEffect of inulin-type fructans on blood lipid profile and glucose level: a systematic review and meta-analysis of randomized controlled trials.Eur J Clin Nutr.(2017-Jan)
  8. ^Collado Yurrita L, San Mauro Martín I, Ciudad-Cabañas MJ, Calle-Purón ME, Hernández Cabria MEffectiveness of inulin intake on indicators of chronic constipation; a meta-analysis of controlled randomized clinical trials.Nutr Hosp.(2014-Aug-01)
  9. ^Watson AW, Houghton D, Avery PJ, Stewart C, Vaughan EE, Meyer PD, de Bos Kuil MJJ, Weijs PJM, Brandt KChanges in stool frequency following chicory inulin consumption, and effects on stool consistency, quality of life and composition of gut microbiota.Food Hydrocoll.(2019-Nov)
  10. ^Dayanne da Silva Borges, Ricardo Fernandes, Arthur Thives Mello, Ethiene da Silva Fontoura, Adair Roberto Soares Dos Santos, Erasmo Benicio Santos de Moraes TrindadePrebiotics may reduce serum concentrations of C-reactive protein and ghrelin in overweight and obese adults: a systematic review and meta-analysisNutr Rev.(2020 Mar 1)
  11. ^Bonnema AL, Kolberg LW, Thomas W, Slavin JLGastrointestinal tolerance of chicory inulin products.J Am Diet Assoc.(2010-Jun)
  12. ^Singh V, Yeoh BS, Chassaing B, Xiao X, Saha P, Aguilera Olvera R, Lapek JD, Zhang L, Wang WB, Hao S, Flythe MD, Gonzalez DJ, Cani PD, Conejo-Garcia JR, Xiong N, Kennett MJ, Joe B, Patterson AD, Gewirtz AT, Vijay-Kumar MDysregulated Microbial Fermentation of Soluble Fiber Induces Cholestatic Liver Cancer.Cell.(2018-Oct-18)
  13. ^An L, Yang JC, Yin H, Xue R, Wang Q, Sun YC, Zhang YZ, Yang MInulin-Type Oligosaccharides Extracted from Yacon Produce Antidepressant-Like Effects in Behavioral Models of Depression.Phytother Res.(2016-Dec)
  14. ^Wang L, Wang Z, Lan Y, Tuo Y, Ma S, Liu XInulin Attenuates Blood-Brain Barrier Permeability and Alleviates Behavioral Disorders by Modulating the TLR4/MyD88/NF-κB Pathway in Mice with Chronic Stress.J Agric Food Chem.(2023-Sep-13)
  15. ^Richard T Liu, Rachel F L Walsh, Ana E SheehanPrebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trialsNeurosci Biobehav Rev.(2019 Jul)
  16. ^Quentin Leyrolle, Renata Cserjesi, Maria D G H Mulders, Giorgia Zamariola, Sophie Hiel, Marco A Gianfrancesco, Daphné Portheault, Camille Amadieu, Laure B Bindels, Sophie Leclercq, Julie Rodriguez, Audrey M Neyrinck, Patrice D Cani, Nicolas Lanthier, Pierre Trefois, Jérome Bindelle, Nicolas Paquot, Miriam Cnop, Jean-Paul Thissen, Olivier Klein, Olivier Luminet, Nathalie M DelzennePrebiotic effect on mood in obese patients is determined by the initial gut microbiota composition: a randomized, controlled trialBrain Behav Immun.(2021 Jan 27)
  17. ^Jackson PP, Wijeyesekera A, Williams CM, Theis S, van Harsselaar J, Rastall RAInulin-type fructans and 2'fucosyllactose alter both microbial composition and appear to alleviate stress-induced mood state in a working population compared to placebo (maltodextrin): the EFFICAD Trial, a randomized, controlled trial.Am J Clin Nutr.(2023-Aug-30)
  18. ^Liber A, Szajewska HEffects of inulin-type fructans on appetite, energy intake, and body weight in children and adults: systematic review of randomized controlled trials.Ann Nutr Metab.(2013)
Examine Database References
  1. Fasting Glucose - Wang L, Yang H, Huang H, Zhang C, Zuo HX, Xu P, Niu YM, Wu SSInulin-type fructans supplementation improves glycemic control for the prediabetes and type 2 diabetes populations: results from a GRADE-assessed systematic review and dose-response meta-analysis of 33 randomized controlled trials.J Transl Med.(2019-Dec-05)
  2. Fasting Glucose - Rao M, Gao C, Xu L, Jiang L, Zhu J, Chen G, Law BYK, Xu YEffect of Inulin-Type Carbohydrates on Insulin Resistance in Patients with Type 2 Diabetes and Obesity: A Systematic Review and Meta-Analysis.J Diabetes Res.(2019)
  3. Low-density lipoprotein (LDL) - Liu F, Prabhakar M, Ju J, Long H, Zhou HWEffect of inulin-type fructans on blood lipid profile and glucose level: a systematic review and meta-analysis of randomized controlled trials.Eur J Clin Nutr.(2017-Jan)
  4. C-Reactive Protein (CRP) - Dayanne da Silva Borges, Ricardo Fernandes, Arthur Thives Mello, Ethiene da Silva Fontoura, Adair Roberto Soares Dos Santos, Erasmo Benicio Santos de Moraes TrindadePrebiotics may reduce serum concentrations of C-reactive protein and ghrelin in overweight and obese adults: a systematic review and meta-analysisNutr Rev.(2020 Mar 1)
  5. Constipation Signs and Symptoms - Collado Yurrita L, San Mauro Martín I, Ciudad-Cabañas MJ, Calle-Purón ME, Hernández Cabria MEffectiveness of inulin intake on indicators of chronic constipation; a meta-analysis of controlled randomized clinical trials.Nutr Hosp.(2014-Aug-01)