Glucomanano, Glucomannane, Konjac Mannan.
Overview InformationGlucomannan is a dietary fiber. It is usually made from the root of the konjac plant. Glucommanan powder, capsules, and tablets are used as medicine.
Glucomannan is used by mouth for constipation, diabetes, and high cholesterol. Some people take glucomannan by mouth for high blood pressure, obesity, and other conditions. But there is no good scientific research to support these other uses of glucomannan.
In foods, glucomannan is used as a thickener or gelling agent. Glucommanan flour and powder are used in food.
How does it work?Glucomannan might work in the stomach and intestines by absorbing water to form a bulky fiber which treats constipation. It may also slow the absorption of sugar and cholesterol from the gut, helping to control sugar levels in diabetes, and reducing cholesterol levels.
Uses & Effectiveness
Possibly Effective for
- Constipation. Taking glucomannan by mouth can relieve constipation in adults. It might also reduce constipation in children, but results are mixed.
- Diabetes. Taking glucomannan by mouth seems to reduce cholesterol, blood sugar levels, and blood pressure in people with diabetes.
- High cholesterol. Taking glucomannan by mouth seems to improve cholesterol levels in people with or without high cholesterol.
Insufficient Evidence for
- Rapid gastric emptying (dumping syndrome). Dumping syndrome occurs when food moves from the stomach to the intestines too quickly. This can cause the body to release a large amount of insulin, which can cause low blood sugar. Some early research shows that taking glucomannan by mouth helps prevent blood sugar from becoming too low after eating in people at risk for this condition. However, not all research agrees.
- A stomach condition called functional gastrointestinal disorder. Early research shows that taking glucomannan does not improve stomach pain, cramping, or bloating in children with this condition.
- High blood pressure. Early research shows that glucomannan might improve blood pressure in people with high blood pressure.
- Overactive thyroid (hyperthyroidism). Early research shows that adding glucomannan to treatment with methimazole and propranolol helps to reduce thyroid hormone levels in people with overactive thyroid.
- Obesity. Some early research shows that taking glucomannan by mouth improves weight loss in overweight and obese adults and children. However, not all research agrees.
- Other conditions.
Side Effects & SafetyGlucomannan powder or flour is LIKELY SAFE when consumed as food. Glucomannan powder and capsules are POSSIBLY SAFE for most adults and children when used in medicinal amounts for up to 4 months. However, solid tablets containing glucomannan are POSSIBLY UNSAFE for adults and LIKELY UNSAFE for children. These can sometimes cause blockages of the throat or intestines.
Special Precautions & Warnings:Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking glucomannan if you are pregnant or breast-feeding. Stay on the safe side and avoid use.
Diabetes: Glucomannan may interfere with blood sugar control. Monitor blood sugar closely if you have diabetes and use glucomannan.
Surgery: Glucomannan might interfere with blood sugar control during and after surgery. Stop using glucomannan at least 2 weeks before a scheduled surgery.
Be cautious with this combination
Medications for diabetes (Antidiabetes drugs) interacts with GLUCOMANNAN
Glucomannan can decrease blood sugar in people with type 2 diabetes. Diabetes medications are also used to lower blood sugar. Taking glucomannan along with diabetes medications might cause your blood sugar to go too low. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.<br/><br/> Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.
Medications taken by mouth (Oral drugs) interacts with GLUCOMANNAN
Glucomannan absorbs substances in the stomach and intestines. Taking glucomannan along with medications taken by mouth can decrease how much medicine your body absorbs, and decrease the effectiveness of your medication. To prevent this interaction, take glucomannan at least one hour after medications you take by mouth.
The following doses have been studied in scientific research:
- For constipation: 2-4.5 grams per day, taken in single or split doses, for up to 12 weeks.
- For high cholesterol: Various glucomannan doses and dosage forms have been used for up to 12 weeks. These include eating biscuits containing 0.5-0.7 grams of glucomannan per 100 kcal, taking 2.4-3.9 grams of glucomannan supplements daily, eating bars containing 3.33 grams of glucomannan three times daily, or eating foods containing 5-10 grams of glucomannan daily.
- For diabetes: 3-4 grams per day for up to 8 weeks. Eating biscuits containing 0.5-0.7 grams of glucomannan per 100 kcal has also been used for 3 weeks. A specific supplement providing 2.5-7.5 grams of glucomannan has also been used with meals.
- For constipation: 100 mg/kg taken once or twice daily (up to a maximum of 5 grams daily) for up to 12 weeks.
- For high cholesterol: 1 gram twice per day for 8 weeks in children aged 6 years and under. 2-3 grams in single or split doses daily for 8 weeks in children aged 6 years and older.
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- Kaats GR, Bagchi D, Preuss HG. Konjac glucomannan dietary supplementation causes significant fat loss in compliant overweight adults. J Am Coll Nutr 2015; Online ahead of print. View abstract
- Keithley JK, Swanson B, Mikolaitis SL, et al. Safety and efficacy of glucomannan for weight loss in overweight and moderately obese adults. J Obes 2013;2013:610908. View abstract.
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- Onakpoya I, Posadzki P, Ernst E. The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trial. J Am Coll Nutr 2014;33(1):70-8. View abstract.
- Passaretti S, Franzoni M, Comin U, et al. Action of glucomannans on complaints in patients affected with chronic constipation: a multicentric clinical evaluation. Ital J Gastroenterol 1991;23:421-5. View abstract.
- Shima K, Tanaka A, Ikegami H, et al. Effect of dietary fiber, glucomannan, on absorption of sulfonylurea in man. Horm Metab Res 1983;15:1-3. View abstract.
- Staiano A, Simeone D, Del Giudice E, et al. Effect of the dietary fiber glucomannan on chronic constipation in neurologically impaired children. J Pediatr 2000;136:41-5. View abstract.
- Vido L, Facchin P, Antonello I, et al. Childhood obesity treatment: double blinded trial on dietary fibres (glucomannan) versus placebo. Padiatr Padol 1993;28:133-6. View abstract.
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- Vuksan V, Jenkins DJ, Spadafora P, et al. Konjac-mannan (glucomannan) improves glycemia and other associated risk factors for coronary heart disease in type 2 diabetes. A randomized controlled metabolic trial. Diabetes Care 1999;22:913-9. View abstract.
- Vuksan V, Sievenpiper JL, Owen R, et al. Beneficial effects of viscous dietary fiber from Konjac-mannan in subjects with the insulin resistance syndrome: results of a controlled metabolic trial. Diabetes Care 2000;23:9-14. View abstract.
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- Zhang, M. Y., Huang, C. Y., Wang, X., Hong, J. R., and Peng, S. S. The effect of foods containing refined Konjac meal on human lipid metabolism. Biomed.Environ.Sci 1990;3(1):99-105. View abstract.
- Arvill A, Bodin L. Effect of short-term ingestion of konjac glucomannan on serum cholesterol in healthy men. Am J Clin Nutr 1995;61:585-9. View abstract.
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- Cairella M, Marchini GAD. [Evaluation of the action of glucomannan on metabolic parameters and on the sensation of satiation in overweight and obese patients]. [Article in Italian] Clin Ter 1995;146:269-74. View abstract.
- Carabin IG, Lyon MR, Wood S, et al. Supplementation of the diet with the functional fiber PolyGlycoplex is well tolerated by healthy subjects in a clinical trial. Nutr J 2009;8:9. View abstract.
- Chen HL, Sheu WH, Tai TS, et al. Konjac supplement alleviated hypercholesterolemia and hyperglycemia in type 2 diabetic subjects--a randomized double-blind trial. J Am Coll Nutr 2003;22:36-42. View abstract.
- Chmielewska A, Horvath A, Dziechciarz P, Szajewska H. Glucomannan is not effective for the treatment of functional constipation in children: a double-blind, placebo-controlled, randomized trial. Clin Nutr 2011;30(4):462-8. View abstract.
- Doi K, Matsuura M, Kawara A, Baba S. Treatment of diabetes with glucomannan (konjac mannan). Lancet 1979;1:987-8.
- Doi K, Matsuura M, Kawara A, et al. Influence of dietary fiber (konjac mannan) on absorption of vitamin B12 and vitamin E (abstract). Tohoku J Exp Med 1983;141:677-81. View abstract.
- Gallaher DD, Gallaher CM, Mahrt GJ, et al. A glucomannan and chitosan fiber supplement decreases plasma cholesterol and increases cholesterol excretion in overweight normocholesterolemic humans. J Am Coll Nutr 2002;21:428-33. View abstract.
- Han Y, Zhang L, Liu XQ, Zhao ZJ, Lv LX. Effect of glucomannan on functional constipation in children: a systematic review and meta-analysis of randomised controlled trials. Asia Pac J Clin Nutr 2017;26(3):471-7. View abstract.
- Henry DA, Mitchell AS, Aylward J, et al. Glucomannan and risk of oesophageal obstruction. Br Med J 1986;292:591-2.
- Ho HVT, Jovanovski E, Zurbau A, et al. A systematic review and meta-analysis of randomized controlled trials of the effect of konjac glucomannan, a viscous soluble fiber, on LDL cholesterol and the new lipid targets non-HDL cholesterol and apolipoprotein B. Am J Clin Nutr 2017;105(5):1239-47. View abstract.
- Azezli, A. D., Bayraktaroglu, T., and Orhan, Y. The use of konjac glucomannan to lower serum thyroid hormones in hyperthyroidism. J Am.Coll.Nutr. 2007;26(6):663-668. View abstract.
- Bernstein, J. A., Crandall, M. S., and Floyd, R. Respiratory sensitization of a food manufacturing worker to konjac glucomannan. J Asthma 2007;44(8):675-680. View abstract.
- Birketvedt, G. S., Shimshi, M., Erling, T., and Florholmen, J. Experiences with three different fiber supplements in weight reduction. Med Sci Monit. 2005;11(1):I5-I8. View abstract.
- Cesa, F., Mariani, S., Fava, A., Rauseo, R., and Zanetti, H. [The use of vegetable fibers in the treatment of pregnancy diabetes and/or excessive wight gain during pregnancy]. Minerva Ginecol. 1990;42(6):271-274. View abstract.
- Chearskul, S., Sangurai, S., Nitiyanant, W., Kriengsinyos, W., Kooptiwut, S., and Harindhanavudhi, T. Glycemic and lipid responses to glucomannan in Thais with type 2 diabetes mellitus. J Med Assoc.Thai. 2007;90(10):2150-2157. View abstract.
- Chen, H. L., Cheng, H. C., Liu, Y. J., Liu, S. Y., and Wu, W. T. Konjac acts as a natural laxative by increasing stool bulk and improving colonic ecology in healthy adults. Nutrition 2006;22(11-12):1112-1119. View abstract.
- Chen, H. L., Cheng, H. C., Wu, W. T., Liu, Y. J., and Liu, S. Y. Supplementation of konjac glucomannan into a low-fiber Chinese diet promoted bowel movement and improved colonic ecology in constipated adults: a placebo-controlled, diet-controlled trial. J Am.Coll.Nutr. 2008;27(1):102-108. View abstract.
- Doi, K., Matsuura, M., Kawara, A., and Baba, S. Treatment of diabetes with glucomannan (konjac mannan). Lancet 5-5-1979;1(8123):987-988. View abstract.
- Fanelli, V., Angelico, F., Stefanutti, C., Calvieri, A., and Fazio, S. [Effects of the integration of a habitual diet with glucomannan fiber in hypercholesterolemia. A clinical study in familial and sporadic hyperlipoproteinemia with lipo-proteic phenotype IIa and IIb]. Clin Ter. 10-15-1986;119(1):17-23. View abstract.
- Gonzalez, Canga A., Fernandez, Martinez N., Sahagun, A. M., Garcia Vieitez, J. J., Diez Liebana, M. J., Calle Pardo, A. P., Castro Robles, L. J., and Sierra, Vega M. [Glucomannan: properties and therapeutic applications]. Nutr.Hosp. 2004;19(1):45-50. View abstract.
- Hopman, W. P., Houben, P. G., Speth, P. A., and Lamers, C. B. Glucomannan prevents postprandial hypoglycaemia in patients with previous gastric surgery. Gut 1988;29(7):930-934. View abstract.
- Huang, C. Y., Zhang, M. Y., Peng, S. S., Hong, J. R., Wang, X., Jiang, H. J., Zhang, F. L., Bai, Y. X., Liang, J. Z., Yu, Y. R., and . Effect of Konjac food on blood glucose level in patients with diabetes. Biomed.Environ.Sci 1990;3(2):123-131. View abstract.
- Kawamura, Y. and Horio, T. [Effects of chewing exercise on the maximum biting force and chewing performance]. Shika.Kiso.Igakkai Zasshi 1989;31(3):281-290. View abstract.
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