Obesity, a risk factor for heart disease, has reached epidemic proportions in the United States. Studies have shown promising benefits of glucomannan, including improved control of blood sugar and improved cholesterol profiles. There have been few adverse effects.
Benefits of Glucomannan as Part of a Healthy Diet
The importance of fiber as part of a healthy diet has long been recognized.2 Intake of soluble (viscous) fiber has been shown to decrease risk factors for heart disease.1 Glucomannan is a very highly soluble form of fiber with promising benefits.4
Benefits of Glucomannan to Control Blood Sugar and Lower Cholesterol
Glucomannan has been studied a lot for its ability to decrease risk factors for heart disease. A study in 1999, reported by the American Diabetes Association, found benefits with glucomannan added to treatment regimens for high-risk diabetics. There was a decrease of several risk factors for heart disease, including better cholesterol ratios and better control of blood sugar after meals.3 Other studies have duplicated these benefits of glucomannan in diabetic patients.5
Glucomannan has been found to be helpful in the treatment of insulin resistance syndrome, a risk for later development of diabetes and heart disease. A January 2000 article studied the benefits of glucomannan when added to high-carbohydrate, low-saturated-fat diets of patients with this syndrome. There was improvement in several risk factors for the type of heart disease that involves the hardening of the walls of blood vessels due to fat deposits. There were significant decreases in total cholesterol and bad cholesterol, bringing these levels into the normal range. Ratios of good fat (HDL) to bad fat (LDL) were improved. Total cholesterol to HDL ratios were also improved. The study concluded that the benefit of glucomannan for improving blood fats was triple the effect seen with oats, guar gum, and psyllium. This advantage was thought to be due to the especially high viscosity of glucomannan. This soluble fiber also increased control of blood sugar in the study participants.4
Adverse Effects of Glucomannan
Adverse effects of glucomannan are generally mild. Some patients have experienced an increase in intestinal gas and loose stools, but these were not severe enough to cause them to discontinue use of glucomannan.3,4,5 In other studies, there were no adverse effects of glucomannan.9 Concerns have been raised that when taken in supplement form, glucomannan may block the esophagus.6 Anyone with a narrowing of the esophagus or a blockage anywhere in the intestinal tract should not take fiber supplements. Fiber supplements should be taken with at least eight ounces of water to avoid extreme swelling and possible blockage of the esophagus. It is also important to drink at least six to eight glasses of water daily in order to avoid constipation.8
In 2001, the FDA recalled candies containing glucomannan due to choking-related deaths in children.7
How to Take Glucomannan
The United States Food and Drug Association has not approved glucomannan to treat any illness and there is no approved dosage for decreasing any of the risk factors for heart disease.
Gelatin capsules may be easier and more pleasing to use than powders.9 The capsules are commonly found in strengths between 500 mg and 666 mg. Powder form is also available and health food stores sell foods containing glucomannan.
A study of the effects of glucomannan benefits in healthy men with elevated cholesterol, but who were not receiving other treatment, found improvements in cholesterol with a dose of three 430 mg capsules three times daily (3.9 grams daily). Capsules were given thirty minutes before meals.9 One study in type 2 diabetic patients also found better control of blood sugar with this dose.5
Other studies that have resulted in the glucomannan benefits of lower cholesterol have used doses between 4 and 13 grams daily. For studies evaluating the control of blood sugar, intake was 500 mg to 700 mg of glucomannan for every 100 calories of food consumed.3,4,8
To avoid gastrointestinal adverse effects of glucomannan, it is advisable to increase the dose gradually.8
Dislcaimer
Please read this disclaimer regarding the information you have just read.
Sources
1. Davidson, Michael H., Lynn D. Dugan, Jill Stocki, Mary R. Dicklin, Kevin C. Maki,, Frances Coletta, Richard Cotter, Max McLeod, and Kenneth Hoersten. "A low-viscosity soluble-fiber fruit juice supplement fails to lower cholesterol in hypercholesterolemic men and women." The Journal of Nutrition 128.11 (November 1998): 1927-1932. 14 Nov 2008.<http://jn.nutrition.org/cgi/content/full/128/11/1927>.
2. Pereira, Mark A., Eilis O'Reilly, Katarina Augustsson, Gary E. Fraser, Uri Goldbourt, Berit L. Heitmann, Goran Hallmans, Paul Knekt, Simin Liu, Pirjo Pietinen, Donna Spiegelman, June Stevens, Jarmo Virtamo, Walter C. Willett, and Alberto Ascherio. "Dietary fiber and risk of coronary heart disease. A pooled analysis of cohort studies." Archives of Internal Medicine 164.4 (23 Feb 2004):370-376. 14 Nov 2008. <http://archinte.ama-assn.org/cgi/content/full/164/4/370>. (subscription is free)
3. Vuksan,V., DJ Jenkins, P Spadafora, JL Sievenpiper, R Owen, E Vidgen, F Brighenti, R Josse, LA Leiter and Charles Bruce-Thompson. "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 22.6 (1999): 913-919. 14 Nov 2008. <http://care.diabetesjournals.org/cgi/content/abstract/22/6/913>. (free full article may be downloaded)
4. Vuksan, Vladimir, John L. Sievenpiper, Robin Owen, Jeffery A. Swilley, Peter Spadafora, David J. A. Jenkins, Edward Vidgen, Furio Brighenti, Robert G. Josse, Lawrence A. Leiter, Zheng Xu, and Renato Novokmet. "Beneficial effects of viscous dietary fiber from konjac-mannan in subjects with the insulin resistance syndrome." Diabetes Care 23.1 (Jan 2000): 9-14. 14 Nov 2008. <http://care.diabetesjournals.org/cgi/content/abstract/23/1/9>.(free full article may be downloaded)
5.Chen, Hsiao-Ling, Wayne Huey-Herng Sheu, Tsai-Sung Tai, Yung-Po Liaw, and Yi-Chuan Chen. "Konjac supplement alleviated hypercholesterolemia and hyperglycemia in type 2 diabetic subjects--A randomized double-blind trial." Journal of the American College of Nutrition 22.1 (2003): 36-42. 14 Nov 2008. <http://www.jacn.org/cgi/reprint/22/1/36>. (free full article may be downloaded)
6.Henry, D.A., A. S. Mitchell, and J. Aylward, et al. "Glucomannan and risk of oesophageal obstruction." British Medical Journal 292 (1986): 591-2.cited by other
7. "Konjac Candy Recall." FDA Recalls Page. 06 Nov 2002. U. S. Food and Drug Administration. 14 Nov 2008 <http://www.fda.gov/oc/po/firmrecalls/topics/konjac.html>.
8. "Fiber." Medical Reference. Complementary Medicine. 01 Apr 2002. University of Maryland Medical Center. 14 Nov 2008 <http://www.umm.edu/altmed/articles/fiber-000303.htm>.
9. Arvill, Anders and Lennart Boden. "Effect of short-term ingestion of konjac glucomannan on serum cholesterol in healthy men." American Journal of Clinical Nutrition 61 (1995): 585-589. 14 Nov 2008. <http://www.ajcn.org/cgi/reprint/61/3/585>.(free full article may be downloaded)