Inulin as a Dietary Fibre
Inulin has been around for many, many years, particularly in its natural source; the chicory root. Chicory is a blue coloured plant that belongs to the same family as the dandelion, historically used as a food source with medicinal properties in the period of the Ancient Egyptians.
Inulin is a dietary fibre, extracted from the roots of the Chicory plant. Dietary fibre is a type of carbohydrate that our bodies can’t digest as we lack the enzymes to breakdown the food item. These fibres are found in edible plants, including vegetables, fruits, dried peas, nuts, lentils and grains (1).
Fibre is grouped into three different categories: soluble, insoluble and resistant starch. Inulin is a soluble fibre that forms a gel-like substance when dissolved in liquid. Soluble fibre has many uses, but it is mainly well-known for its ability to reduce cholesterol absorption by binding cholesterol to the gut so that it can’t be absorbed in the bloodstream (2).
What is Inulin?
Inulin is a heterogeneous blend of fructose polymers, dispersed in plant-based carbohydrates, such as chicory. The chicory root is known for its use as a coffee substitute however, there are many other benefits to the root and the powder blend which we know as Inulin, as you will discover now (3).
Inulin is made up of several chains of fructose molecules which are linked together in a way that our bodily enzymes can’t digest, hence its status as a soluble fibre. The chicory plant is a natural source of Inulin, providing around 36-48g of Inulin for every 100g of the plant or root.
Health benefits of Inulin
The European Food Safety Authority (EFSA) acknowledges that Inulin from a chicory root source contributes to normal bowel function by increasing the frequency of stools. The consumer must consume at least 12g of chicory-derived Inulin in order to achieve the desired effect, which is, ultimately, to reduce symptoms of constipation. EFSA also acknowledges that Inulin is a soluble, prebiotic and fermentable dietary fibre which does not trigger glucose release in the small intestine. In addition, the soluble fibre is demonstrated to provide selective prebiotic fermentation by the colonic microbiota, supporting the good bacteria to create a healthy microbiota (4).
This soluble fibre is very versatile and can be used in both baking and cooking as a substitute nutritional addition, as well as in dietary interventions. Inulin has a low caloric value at just 1.5 kilocalories per gram, making it suitable to use in baking as a sugar replacer to aid weight loss. Studies also suggest that adding just 10g of Inulin to a carbohydrate-rich diet each day can reduce blood lipogenesis and plasma triacylglycerol concentrations, therefore reducing your risk of atherosclerosis (clotting of the arteries due to fat deposits) (5).
As a soluble fibre, Inulin lowers the pH of the intestine due to its fibre-like results which affect the acidity of the gut. This helps to relieve symptoms of constipation, a characteristic that is furthered by Inulin’s similar physical properties to that of pectin and guar gum, increasing the wet faecal mass by 1.5-2g of every 1g of Inulin consumed (6).
Furthermore, Inulin is thought to benefit the absorption of minerals, including calcium, magnesium and iron. As colonic fermentation takes place to produce short-chain fatty acids, a decrease in the pH of the large intestine occurs. This reduced pH increases the bioavailability of calcium, enhancing absorption of the mineral (7).
Lastly, Inulin has been recognised as an ingredient that plays a role in the regulation of food intake and appetite. Research suggests that Inulin enhances the production of GLP-1 (Glucagon-like-peptide-1) which increases blood GLP-1 levels and decreases the level of ghrelin that is secreted, a hormone that stimulates hunger levels (8).
1. Nestle (2019) Dietary Fibre. Available at https://www.nestle.co.nz/nhw/nutritionfactsheets/dietaryfibre.
2. Vuksan, V., Jenkins, A. L., Rogovik, A. L., Fairgrieve, C. D., Jovanovski, E. and Leiter, L. A. (2011) 'Viscosity rather than quantity of dietary fibre predicts cholesterol-lowering effect in healthy individuals', British Journal of Nutrition, 106, 1349 - 1352. Available at: https://www.researchgate.net/profile/Lawrence_Leiter/publication/51474615_Viscosity_rather_than_quantity_of_dietery_fibre_predicts_cholestorl-lowering_effect_in_healthy_individuals/links/54044de30cf23d9765a6131f/Viscosity-rather-than-quantity-of-dietery-fibre-predicts-cholestorl-lowering-effect-in-healthy-individuals.pdf.
3. Niness, K. R. (1999) 'Inulin and Oligofructose: What Are They?', The Journal of Nutrition, 129(7), 1402S - 1406S. Accessed at: https://academic.oup.com/jn/article/129/7/1402S/4722577.
4. European Food Safety Authority. (2015) 'Scientific Opinion on the substantiation of a health claim related to “native chicory inulin” and maintenance of normal defecation by increasing stool frequency pursuant to Article 13.5 of Regulation (EC) No 1924/20061', EFSA Journal, 13(1), 3951 - 3963. Available at: https://efsa.onlinelibrary.wiley.com/doi/epdf/10.2903/j.efsa.2015.3951
Scholz-Ahrens, K. E. and Schrezenmeir, J. (2002) 'Inulin: oligofructose and mineral metabolism—experimental data and mechanism', British Journal of Nutrition, 87, S179–S186.
8. Choo, J. H., Jung, C. H., Kang, J. M., Kim, B. G., Kim, S. W. and Kim, S. W. (2009) 'Clinical Analysis of Sinonasal Inverted Papilloma according to the Staging System', Korean Journal of Otorhinolaryngology - head and neck surgery, 52, 41-45. Available at: http://www.kjorl.org/articles/search_result.php?term=author&f_name=Sung%20Won&l_name=Kim.