Glucomannan is a substance extracted from the root of the konjac (a plant native to Asia). Glucomannan is rich in soluble fiber, the type of dietary fiber that attracts water and turns to gel during digestion. Long used in traditional Chinese medicine, glucomannan is now sold as a dietary supplement and weight loss aid.
Uses for Glucomannan
In addition, glucomannan is purported to promote weight loss and slow the aging process. Some proponents suggest that glucomannan can also improve thyroid health and even fight some forms of cancer (such as lung cancer).
Benefits of Glucomannan
Although research on the health effects of glucomannan is somewhat limited, several studies suggest that glucomannan may offer certain health benefits. Here's a look at some key findings from the available research on glucomannan:
1) Glucomannan and Weight Loss
In a research review published in Alternative Therapies in Health and Medicine in 2005, scientists found that taking glucomannan in doses of two to four grams per day may result in significant weight loss among overweight and obese individuals. According to the review's authors, glucomannan may help promote weight loss by increasing satiety (the feeling of fullness after eating).
While glucomannan shows promise as a weight loss aid, the review's authors note that more research is needed to determine the safety and efficacy of taking glucomannan for weight loss.
2) Glucomannan and Cholesterol
Glucomannan may help keep cholesterol in check, suggests a 2008 report published in the American Journal of Clinical Nutrition. After analyzing 14 clinical trials on glucomannan, the report's authors concluded that glucomannan may lower total cholesterol and LDL ("bad") cholesterol. In addition, glucomannan appeared to reduce body weight and cut levels of triglycerides (harmful blood fats). However, the report's authors note that glucomannan does not seem to affect HDL ("good") cholesterol or blood pressure.
3) Glucomannan and Constipation
Glucomannan may help treat childhood constipation, according to a 2004 study published in Pediatrics. The study involved 46 chronically constipated children, each of whom was treated with either glucomannan or a placebo for four weeks. Among the 31 children who completed the study, researchers found that glucomannan was more effective in alleviating constipation. Glucomannan also appeared to reduce abdominal pain.
4) Glucomannan and Rheumatoid Arthritis
Glucomannan may help manage rheumatoid arthritis, according to preliminary research published in Neuro Endocrinology Letters. In tests on rats, the authors of a 2008 study found that certain antioxidants and anti-inflammatory compounds available in glucomannan may be beneficial in the treatment of rheumatoid arthritis.
Is Glucomannan Safe?
Little is known about the safety of using glucomannan in the long term. However, there's some evidence that glucomannan may produce certain side effects (such as flatulence, abdominal pain, and digestive problems). If you're considering the use of glucomannan, talk to your doctor before beginning treatment.
Where to Find Glucomannan
Widely available for purchase online, glucomannan powder, capsules, and tablets are sold in many natural-food stores and in stores specializing in dietary supplements.
Bauerova K, Ponist S, Navarova J, Dubnickova M, Paulovicova E, Pajtinka M, Kogan G, Mihalova D. "Glucomannan in prevention of oxidative stress and inflammation occurring in adjuvant arthritis." Neuro Endocrinol Lett. 2008 Oct;29(5):691-6.
Chua M, Baldwin TC, Hocking TJ, Chan K. "Traditional uses and potential health benefits of Amorphophallus konjac K. Koch ex N.E.Br." J Ethnopharmacol. 2010 Mar 24;128(2):268-78.
Keithley J, Swanson B. "Glucomannan and obesity: a critical review." Altern Ther Health Med. 2005 Nov-Dec;11(6):30-4.
González Canga A, Fernández Martínez N, Sahagún AM, García Vieitez JJ, Díez Liébana MJ, Calle Pardo AP, Castro Robles LJ, Sierra Vega M. "Glucomannan: properties and therapeutic applications." Nutr Hosp. 2004 Jan-Feb;19(1):45-50.
Loening-Baucke V, Miele E, Staiano A. "Fiber (glucomannan) is beneficial in the treatment of childhood constipation." Pediatrics. 2004 Mar;113(3 Pt 1):e259-64.
Sood N, Baker WL, Coleman CI. "Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis." Am J Clin Nutr. 2008 Oct;88(4):1167-75.