Plant Profiler

Psyllium (Plantago ovata)

Psyllium (Plantago ovata) Image
Synonyms / Common Names / Related Terms
Arabinose, Bran Buds® cereal, bulk laxative, Effersyllium®, fiber, Fiberall®, Fiber-loop cereal, flea seed, fleawort, Fybogel®, Heartwise® cereal, hemicellulose, Hydrocil®, Indian plantago seed, isabgol, I-so-gel®, ispaggol, ispaghula, ispaghula husk, ispaghula seed, Konsyl®, Lunelax®, Metamucil®, Minolest®, natural vegetable laxative, pale psyllium, Perdiem®, Plantago arenaria, Plantago isphagula, Plantago ovata, Plantago ovata Forsk., Plantago ovata husks, Plantago psyllium, plantago seed, prebiotic, Prodiem Plain®, psyllion, psyllios, psyllium, psyllium husk, psyllium husk powder, psyllium hydrophilic mucilloid, psyllium seed, psyllium seed husks, Regulan®, Serutan®, soluble fiber, spogel, Vi-Siblin®, xylose, Yerba Prima®.

Mechanism of Action


  • Constituents: Psyllium is derived from Plantago ovata. The husks of the seeds are more commonly used, but the seeds themselves have also been administered. Psyllium is a mixture of polysaccharides: pentoses, hexoses, and uronic acids. Seed preparations contain approximately 47% soluble fiber by weight and husk preparations generally consist of 67-71% soluble fiber and approximately 85% total fiber by weight.13,14
  • Psyllium has the highest level of soluble dietary fiber of any grain source. It is hydrophilic because of its high content of hemicelluloses.12,1
  • Psyllium is somewhat resistant to fermentation. Its arabinose and xylose sugars have been found to be 24% and 53% "digestible," respectively. Its intestinal "bulking" effect is due largely to intact material.4,25
  • Allergic reaction effects: IgE-mediated allergic mechanism is probably responsible for the allergic symptoms in many individuals with repeated psyllium exposures.26
  • Anti-inflammatory effects: Five phenylethyanoids were isolated from Plantago lanceolata herbage and tested in mice with arachidonic acid-induced mouse ear edema. Acetoside and plantamajoside were found to have an anti-edema effect.11
  • Chemoprotective effects: Psyllium alone does not affect the absorption of carcinogens in the gastrointestinal tract, and the soluble fiber formed by psyllium does not bind to carcinogens. Some evidence suggests that psyllium might improve the chemoprotective effect of wheat bran.22 Psyllium might help maintain normal cell proliferation in the colon.23,24 Psyllium fiber is converted to butyrate, which appears to be important in protecting against colon cancer.15
  • Cholesterol-lowering effects: Studies on the effects of psyllium on cholesterol absorption have been conflicting.16,14,17,27,28,6,29 One proposed hypocholesterolemic effect of psyllium is "displacement" of dietary fat by soluble fiber.30,12,31. Psyllium in the diet may simply displace fats and cholesterol in the diet, reducing the amount available for absorption, but not directly affecting cholesterol. Psyllium has been shown to increase fecal excretion of bile acids and cholesterol, bind bile acids and cholesterol in the intestines, allow less circulation for reabsorption, and cause the liver to use more cholesterol to make bile acids.30 Fatty acids, propionate and acetate, had an indirect inhibitory effect on cholesterol in the liver. These fatty acids are produced from soluble fiber by bacteria in the colon. In a human study, psyllium lowered LDL, decreased cholesterol absorption, and increased the fractional turnover of both chenodeoxycholic and cholic acids.16 The authors' conclusion was that psyllium lowered LDL primarily via the stimulation of bile acid synthesis. Other researchers have also come to similar conclusions.32 Hypocholesterolemic effects of psyllium are possibly imparted through increased fecal bile acid elimination, with a compensatory increase in bile acid synthesis. A single animal study found that psyllium, when added to pre-existing cholestyramine therapy, reduced hepatic cholesterol content and reversed the LDL receptor suppression induced by single-agent resin therapy.21 The hypocholesterolemic action of psyllium and plant sterols can be explained in part by modifications in the intravascular processing of lipoproteins and by increases in LDL receptor-mediated uptake.33 Psyllium exhibited viscous characteristics throughout small intestinal simulation, indicating potential for these fibers to elicit blood glucose and lipid attenuation.34
  • Gastrointestinal effects: The laxative properties of psyllium are due to the swelling of the husk when it comes in contact with water. The polysaccharides in psyllium that form into a gel in the intestine also lubricate stool contents and provide greater ease during defecation.8 The resulting bulk stimulates a reflex contraction of the walls of the bowel, followed by emptying.35 Studies exploring the mechanism of the laxative effects of psyllium have been somewhat conflicting, but have generally revealed an increase in bowel movements daily, an increase in wet and dry stool weight, and a decrease in total gut transit time with psyllium administration.2,3,4,5,6. In persons with diarrhea, the mucilage may increase the water-holding capacity and viscosity of stools, which delays gastric emptying and improves stool consistency.7,8,9,10 Psyllium maintains remission in ulcerative colitis since fermentation of blond psyllium in the colon yields butyrate, a short-chain fatty acid known to inhibit cytokine production and have an anti-inflammatory effect.20 With irritable bowel syndrome, blond psyllium may normalize bowel function and relieve symptom severity by reducing rectosigmoidal pressure 36.
  • Glucose-lowering effects: The glucose-lowering effects of psyllium may be mediated by its slowing the access of glucose to the small intestine, delaying gastric emptying, or through carbohydrate digestion and absorption.18,19,37 Psyllium appears to decrease hyperglycemia in response to dextrose intake, when it is given simultaneously with dextrose, possibly by interfering with glucose intestinal absorption.38 Psyllium exhibited viscous characteristics throughout small intestinal simulation, indicating the potential for these fibers to elicit blood glucose and lipid attenuation.34


  • Psyllium remains predominantly in the gut as a "bulk" agent. It is somewhat resistant to fermentation and is passed largely unchanged through the gastrointestinal tract.4,25 It has significant "water-holding" capacity due to its high hemicellulose content.12 Onset of action is 12-24 hours; full effect may take 2-3 days.39
  • A breakfast cereal that provided 6.6g of psyllium soluble fiber significantly lowered area under the curve (AUC) values for plasma glucose and insulin compared to breakfast cereal that provided zero psyllium soluble fiber. Additionally, the free fatty acids were found to be higher in the cereal with the psyllium fiber.40


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  2. Cherbut, C., Bruley, des, V, Schnee, M., Rival, M., Galmiche, J. P., and Delort-Laval, J. Involvement of small intestinal motility in blood glucose response to dietary fibre in man. Br J Nutr 1994;71(5):675-685. 8054323
  3. Cheskin, L. J., Kamal, N., Crowell, M. D., Schuster, M. M., and Whitehead, W. E. Mechanisms of constipation in older persons and effects of fiber compared with placebo. J Am Geriatr Soc 1995;43(6):666-669. 7775727
  4. Marteau, P., Flourie, B., Cherbut, C., Correze, J. L., Pellier, P., Seylaz, J., and Rambaud, J. C. Digestibility and bulking effect of ispaghula husks in healthy humans. Gut 1994;35(12):1747-1752. 7829013
  5. McRorie, J. W., Daggy, B. P., Morel, J. G., Diersing, P. S., Miner, P. B., and Robinson, M. Psyllium is superior to docusate sodium for treatment of chronic constipation. Aliment Pharmacol Ther 1998;12(5):491-497. 9663731
  6. Miettinen, T. A. and Tarpila, S. Serum lipids and cholesterol metabolism during guar gum, plantago ovata and high fibre treatments. Clin Chim Acta 8-31-1989;183(3):253-262. 2553302
  7. Bliss, D. Z., Jung, H. J., Savik, K., Lowry, A., LeMoine, M., Jensen, L., Werner, C., and Schaffer, K. Supplementation with dietary fiber improves fecal incontinence. Nurs Res 2001;50(4):203-213. 11480529
  8. Marlett, J. A., Kajs, T. M., and Fischer, M. H. An unfermented gel component of psyllium seed husk promotes laxation as a lubricant in humans. Am J Clin Nutr 2000;72(3):784-789. 10966900
  9. Washington, N., Harris, M., Mussellwhite, A., and Spiller, R. C. Moderation of lactulose-induced diarrhea by psyllium: effects on motility and fermentation. Am J Clin Nutr 1998;67(2):317-321. 9459381
  10. Watson WC, Corke M, Pomare EW, and et al. A double blind study on the effect on stool frequency and appearance, abdominal symptoms and serum lipid levels in patients with the irritable bowel syndrome (Abstract). Gastroenterology 1977;72:1146.
  11. Murai, M., Tamayama, Y., and Nishibe, S. Phenylethanoids in the herb of Plantago lanceolata and inhibitory effect on arachidonic acid-induced mouse ear edema. Planta Med 1995;61(5):479-480. 7480214
  12. Glore, S. R., Van Treeck, D., Knehans, A. W., and Guild, M. Soluble fiber and serum lipids: a literature review. J Am Diet Assoc 1994;94(4):425-436. 8144811
  13. Davidson, M. H., Maki, K. C., Kong, J. C., Dugan, L. D., Torri, S. A., Hall, H. A., Drennan, K. B., Anderson, S. M., Fulgoni, V. L., Saldanha, L. G., and Olson, B. H. Long-term effects of consuming foods containing psyllium seed husk on serum lipids in subjects with hypercholesterolemia. Am J Clin Nutr 1998;67(3):367-376. 9497178
  14. Gelissen, I. C., Brodie, B., and Eastwood, M. A. Effect of Plantago ovata (psyllium) husk and seeds on sterol metabolism: studies in normal and ileostomy subjects. Am J Clin Nutr 1994;59(2):395-400. 8310991
  15. Nordgaard, I., Hove, H., Clausen, M. R., and Mortensen, P. B. Colonic production of butyrate in patients with previous colonic cancer during long-term treatment with dietary fibre (Plantago ovata seeds). Scand J Gastroenterol 1996;31(10):1011-1020. 8898423
  16. Everson, G. T., Daggy, B. P., McKinley, C., and Story, J. A. Effects of psyllium hydrophilic mucilloid on LDL-cholesterol and bile acid synthesis in hypercholesterolemic men. J Lipid Res 1992;33(8):1183-1192. 1431597
  17. Jenkins, D. J., Wolever, T. M., Rao, A. V., Hegele, R. A., Mitchell, S. J., Ransom, T. P., Boctor, D. L., Spadafora, P. J., Jenkins, A. L., Mehling, C., and . Effect on blood lipids of very high intakes of fiber in diets low in saturated fat and cholesterol. N Engl J Med 7-1-1993;329(1):21-26. 8389421
  18. Anderson, J. W., Allgood, L. D., Turner, J., Oeltgen, P. R., and Daggy, B. P. Effects of psyllium on glucose and serum lipid responses in men with type 2 diabetes and hypercholesterolemia. Am J Clin Nutr 1999;70(4):466-473. 10500014
  19. Pastors, J. G., Blaisdell, P. W., Balm, T. K., Asplin, C. M., and Pohl, S. L. Psyllium fiber reduces rise in postprandial glucose and insulin concentrations in patients with non-insulin-dependent diabetes. Am J Clin Nutr 1991;53(6):1431-1435. 1852093
  20. Fernandez-Banares, F., Hinojosa, J., Sanchez-Lombrana, J. L., Navarro, E., Martinez-Salmeron, J. F., Garcia-Puges, A., Gonzalez-Huix, F., Riera, J., Gonzalez-Lara, V., Dominguez-Abascal, F., Gine, J. J., Moles, J., Gomollon, F., and Gassull, M. A. Randomized clinical trial of Plantago ovata seeds (dietary fiber) as compared with mesalamine in maintaining remission in ulcerative colitis. Spanish Group for the Study of Crohn's Disease and Ulcerative Colitis (GETECCU). Am J Gastroenterol 1999;94(2):427-433. 10022641
  21. Turley, S. D., Daggy, B. P., and Dietschy, J. M. Effect of feeding psyllium and cholestyramine in combination on low density lipoprotein metabolism and fecal bile acid excretion in hamsters with dietary-induced hypercholesterolemia. J Cardiovasc Pharmacol 1996;27(1):71-79. 8656662
  22. Alabaster, O., Tang, Z., and Shivapurkar, N. Dietary fiber and the chemopreventive modelation of colon carcinogenesis. Mutat Res 2-19-1996;350(1):185-197. 8657180
  23. Alabaster, O., Tang, Z. C., Frost, A., and Shivapurkar, N. Potential synergism between wheat bran and psyllium: enhanced inhibition of colon cancer. Cancer Lett 11-30-1993;75(1):53-58. 8287381
  24. Gerber, M. Fiber and breast cancer: another piece of the puzzle--but still an incomplete picture. J Natl Cancer Inst 7-3-1996;88(13):857-858. 8656432
  25. Wolever, T. M., ter Wal, P., Spadafora, P., and Robb, P. Guar, but not psyllium, increases breath methane and serum acetate concentrations in human subjects. Am J Clin Nutr 1992;55(3):719-722. 1312763
  26. Marks, G. B., Salome, C. M., and Woolcock, A. J. Asthma and allergy associated with occupational exposure to ispaghula and senna products in a pharmaceutical work force. Am Rev Respir Dis 1991;144(5):1065-1069. 1952432
  27. Jenkins, D. J., Wolever, T. M., Vidgen, E., Kendall, C. W., Ransom, T. P., Mehling, C. C., Mueller, S., Cunnane, S. C., O'Connell, N. C., Setchell, K. D., Lau, H., Teitel, J. M., Garvey, M. B., Fulgoni, V., III, Connelly, P. W., Patten, R., and Corey, P. N. Effect of psyllium in hypercholesterolemia at two monounsaturated fatty acid intakes. Am J Clin Nutr 1997;65(5):1524-1533. 9129487
  28. Leng-Peschlow, E. Plantago ovata seeds as dietary fibre supplement: physiological and metabolic effects in rats. Br J Nutr 1991;66(2):331-349. 1662073
  29. Trautwein, E. A., Siddiqui, A., and Hayes, K. C. Modeling plasma lipoprotein-bile lipid relationships: differential impact of psyllium and cholestyramine in hamsters fed a lithogenic diet. Metabolism 1993;42(12):1531-1540. 8246766
  30. Chan, E. K. and Schroeder, D. J. Psyllium in hypercholesterolemia. Ann Pharmacother 1995;29(6):625-628. 7663036
  31. Turnbull, W. H. and Thomas, H. G. The effect of a Plantago ovata seed containing preparation on appetite variables, nutrient and energy intake. Int J Obes Relat Metab Disord 1995;19(5):338-342. 7647826
  32. Matheson, H. B. and Story, J. A. Dietary psyllium hydrocolloid and pectin increase bile acid pool size and change bile acid composition in rats. J Nutr 1994;124(8):1161-1165. 8064365
  33. Shrestha, S., Freake, H. C., McGrane, M. M., Volek, J. S., and Fernandez, M. L. A combination of psyllium and plant sterols alters lipoprotein metabolism in hypercholesterolemic subjects by modifying the intravascular processing of lipoproteins and increasing LDL uptake. J Nutr 2007;137(5):1165-1170. 17449576
  34. Dikeman, C. L., Murphy, M. R., and Fahey, G. C., Jr. Dietary fibers affect viscosity of solutions and simulated human gastric and small intestinal digesta. J Nutr 2006;136(4):913-919. 16549450
  35. Leung AY and Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics 1996;2d ed.:427-429.
  36. Cook, I. J., Irvine, E. J., Campbell, D., Shannon, S., Reddy, S. N., and Collins, S. M. Effect of dietary fiber on symptoms and rectosigmoid motility in patients with irritable bowel syndrome. A controlled, crossover study. Gastroenterology 1990;98(1):66-72. 2152777
  37. Wolever, T. M., Vuksan, V., Eshuis, H., Spadafora, P., Peterson, R. D., Chao, E. S., Storey, M. L., and Jenkins, D. J. Effect of method of administration of psyllium on glycemic response and carbohydrate digestibility. J Am Coll Nutr 1991;10(4):364-371. 1654354
  38. Frati-Munari, A. C., Castillo-Insunza, M. R., Riva-Pinal, H., Ariza-Andraca, C. R., and Banales-Ham, M. Effect of Plantago psyllium mucilage on the glucose tolerance test. Arch Invest Med (Mex) 1985;16(2):191-197. 3907568
  39. Levy MH. Constipation and diarrhea in cancer patients. Cancer Bull 1991;43(5):412-422.
  40. Clark, C. A., Gardiner, J., McBurney, M. I., Anderson, S., Weatherspoon, L. J., Henry, D. N., and Hord, N. G. Effects of breakfast meal composition on second meal metabolic responses in adults with Type 2 diabetes mellitus. Eur J Clin Nutr 2006;60(9):1122-1129. 16670695

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