Hostname: page-component-594f858ff7-wfvfs Total loading time: 0 Render date: 2023-06-08T00:24:46.320Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": true, "coreDisableEcommerce": false, "corePageComponentUseShareaholicInsteadOfAddThis": true, "coreDisableSocialShare": false, "useRatesEcommerce": true } hasContentIssue false

The active fraction of psyllium seed husk

Published online by Cambridge University Press:  05 March 2007

Judith A. Marlett*
Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, Wisconsin, 53706, USA
Milton H. Fischer
Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, Wisconsin, 53706, USA
*Corresponding author: Dr J. A. Marlett, fax +1 608 262 5860,
Rights & Permissions[Opens in a new window]


HTML view is not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

A series of experiments and evaluations of fractions isolated from psyllium seed husk (PSH) were used to test the overall hypothesis that a gel-forming component of PSH is not fermented and that it is this component that is responsible for the laxative and cholesterol-lowering properties of PSH. A gel is isolated from human stools collected during a controlled diet study when PSH is consumed but not when the control diet only is consumed. Evaluations of three fractions isolated from PSH suggest that gel-forming fraction B, which is about 55% of PSH, is poorly fermented and is the component that increases stool moisture and faecal bile acid excretion, the latter leading to lower blood cholesterol levels. Fraction C, representing <15% of PSH, is viscous, but is rapidly fermented. Fraction A is alkali-insoluble material that is not fermented. In concentrations comparable with their presence in PSH, fractions A and C do not alter moisture and bile acid output. The active fraction of PSH is a highly-branched arabinoxylan consisting of a xylose backbone and arabinose- and xylose-containing side chains. In contrast to arabinoxylans in cereal grains that are extensively fermented, PSH possesses a structural feature, as yet unidentified, that hinders its fermentation by typical colonic microflora.

Session: Physiological aspects of fibre
Copyright © The Nutrition Society 2003


Anderson, JW, Allgood, LD, Lawrence, A, Altringer, LA, Jerdack, GR, Hengegold, DA (2000) Cholesterol-lowering effects of psyllium intake adjunctive to diet therapy in men and women with hypercholesterolemia: meta-analysis of 8 controlled trials. American Journal of Clinical Nutrition 71, 472479.Google ScholarPubMed
Cabotaje, LM, Shinnick, FL, Lopéz-Guisa, JM, Marlett, JA (1994) Mucin secretion in germfree rats fed fiber-free and psyllium diets and bacterial mass and carbohydrate fermentation after colonization. Applied Environmental Microbiology 60, 13021307.Google ScholarPubMed
Chen, H-L, Haack, VS, Janecky, CW, Vollendorf, NW, Marlett, JA (1998) Mechanisms by which wheat bran and oat bran increase stool weight in humans. American Journal of Clinical Nutrition 68, 711719.Google ScholarPubMed
Cummings, JH (1993) The effect of dietary fiber on fecal weight and composition. In Dietary Fiber in Human Nutrition, pp.263349 [Spiller, GA, editors]. Boca Raton, FL: CRC Press.Google Scholar
Harvey, RF, Pomare, EW, Heaton, KW (1973) Effects of increased dietary fibre on intestinal transit time. Lancet i, 12781280.CrossRefGoogle Scholar
Hildebrandt, LA, Marlett, JA (1991) Starch bioavailability in the upper gastrointestinal tract of colectomized rats. Journal of Nutrition 121, 679686.Google ScholarPubMed
Kennedy, JF, Sandhu, JS, Southgate, DAT (1979) Structural data for the carbohydrate of ispaghula husk ex Plantago ovata Forsk. Carbohydrate Research 75, 265274.CrossRefGoogle Scholar
Laidlaw, RA, Percival, EGV (1950) Studies of seed mucilages. Part V. Examination of a polysaccharide extracted from the seeds of Plantago ovata Forsk by hot water Journal of the Chemical Society. 528534.CrossRefGoogle Scholar
Marlett, JA &, Fischer, MH (2001) Unfermented gel fraction from psyllium seed husks. US Patent no. 6287609, issued 11 September 2001.Google Scholar
Marlett, JA, Fischer, MH (2002) A poorly fermented gel from psyllium seed husk increases excreta moisture and bile acid excretion in the rat. Journal of Nutrition 132, 26382643.Google Scholar
Marlett, JA, Kajs, TM, Fischer, MH (2000) An unfermented gel component of psyllium seed husk promotes laxation as a lubricant in humans. American Journal of Clinical Nutrition 72, 784789.Google ScholarPubMed
Marteau, P, Flourié, B, Cherbut, C, Corrèze, J-L, Pellier, P, Seylaz, J, Rambaud, J-C (1994) Digestibility and bulking effect of ispaghula husks in healthy humans. Gut 35, 17471752.CrossRefGoogle ScholarPubMed
Monsma, DJ, Marlett, JA (1995) Rat cecal inocula produce different patterns of short-chain fatty acids than fecal inocula in in vitro fermentations. Journal of Nutrition 125, 24632470.Google ScholarPubMed
Monsma, DJ, Marlett, JA (1996) Fermentation of carbohydrate in rat ileal digesta was enhanced with cecal inocula compared to fecal inocula. Journal of Nutrition 126, 554563.Google Scholar
Setchell, KDR, Lawson, AM, Tanida, N, Sjöval, J (1985) General method for the analysis of metabolic profiles of bile acids and related compounds in feces. Journal of Lipid Research 24, 10851100.Google ScholarPubMed
Tandon, R, Axelson, M, Sjöval, J (1984) Selective liquid chromatographic isolation and gas chromatographic-mass spectrometric analysis of ketonic bile acids in faeces. Journal of Chromatography 302, 114.CrossRefGoogle ScholarPubMed