National Institutes of Health. Dietary Reference Intakes (DRIs): Recommended Dietary Allowances and Adequate Intakes, Total Water and Macronutrients. Glucomannan is used 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 evidence to support these other uses of glucomannan. Several trials found that the participants given Glucomannan lost significantly more body weight than the placebo group. Interestingly they found that the only study into use of a Glucomannan as a weight loss supplement in children found no difference in those given Glucomannan compared to the placebo group, as both groups of children lost a significant amount of body weight during the trial. On the other hand, another review, investigating Glucomannan and obesity, did find that some studies had favourable results in children too 4. Matsuura, Y. Degradation of konjac glucomannan by enzymes in human feces and formation of short-chain fatty acids by intestinal anaerobic bacteria. J Nutr.Sci Vitaminol.(Tokyo) 1998;44(3):423-436. View abstract. Mortensen A, Aguilar F, Crebelli, et al. EFSA Panel on Food Additives and Nutrient Sources added to Food. Re-evaluation of konjac gum (E 425 i) and konjac glucomannan (E425 ii) as food additives. EFSA Journal 2017;15(6):4864. View abstract.

Again the beneficial effect is obtained with a daily intake of 3 g of glucomannan in three doses of 1 g each, together with 1-2 glasses of water, before meals and in the context of an energy-restricted diet. Glucomannan is a complex sugar that may lower cholesterol and blood sugar and prevent constipation. Early research suggests that it may also be helpful for managing weight, improving gut health, and protecting the skin. Read on for more about its potential.

More about glucomannan

Keithley, J. and Swanson, B. Glucomannan and obesity: a critical review. Altern.Ther.Health Med 2005;11(6):30-34. View abstract. Glucomannan is a natural water-soluble fiber that can help reduce cholesterol and blood sugar levels, and can improve gut and skin health. The fiber is extracted from the konjac root, a plant native to Asia, and is available as a supplement. It helps promote larger stools and improve digestion. It also delays the absorption of sugar, which may help with diabetes. Despite its potential benefits, glucomannan has a long and storied history as a dietary fiber.

Fazelian S, Rouhani MH, Bank SS, Amani R. Chromium supplementation and polycystic ovary syndrome: A systematic review and meta-analysis. J Trace Elem Med Biol. 2017;42:92-96. doi:10.1016/j.jtemb.2017.04.008 Glucomannan’s function when used as a dietary supplement is as a water-soluble, highly viscous, fermentable, dietary fibre1,4. It is these characteristics of Glucomannan that allow it to act as a coating for the digestive tract, to soak up water in the gut, bulk up the gut, improve gut transit time and reduce the absorption of cholesterol1,2,4. In another trial, 2.4 g/day of chitosan and glucomannan reduced total, LDL, and HDL cholesterol but not triglycerides in 21 overweight people [ 11]. 2) Diabetes 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. In the past there have been some cases reported of obstruction of the oesophagus after ingestion of Glucomannan tablets or chewable jellies 4. This is likely because the Glucomannan absorbed water before it reached the stomach, causing it to swell and obstruct the throat resulting in choking. This is no longer an issue now that it is available only as a cellulose capsule or powder to be mixed with water, as the capsule protects the powder until it reaches the stomach 4. It’s important to note that for these reasons Glucomannan capsules should be swallowed whole, do not open them.Glucomannan is a natural prebiotic, meaning, in essence, that it helps to “feed” probiotics, or beneficial gut flora. Konjac acts as a natural laxative by increasing stool bulk and improving colonic ecology in healthy adults. 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.

Glucomannan is made from the root of the Konjac plant, which grows in tropical and subtropical regions of Asia. The plant’s corm is a similar shape to a yam and contains a fiber-like substance called glucomannan. It is often milled into a fine powder and sold as glucomannan flour. It can also be found in shirataki noodles, which are highly nutritious. Our team comprises of trained MDs, PhDs, pharmacists, qualified scientists, and certified health and wellness specialists. Glucomannan is an excellent food supplement for diabetics, because it creates a feeling of fullness and causes people to eat less. As a source of soluble fiber, glucomannan helps with digestion and the absorption of sugar and cholesterol. Compared to other weight-loss supplements, glucomannan is safe for the kidneys. Besides suppressing appetite, it also regulates blood sugar levels and insulin resistance. National Institutes of Health. Office of Dietary Supplements. Chromium: Fact sheet for health professionals.A recent pilot study published in the Journal of Functional Foods investigated the use of Glucomannan supplements taken in conjunction with chromium and oligofructose (a dietary prebiotic fibre) and a calorie-controlled controlled diet, by women who were overweight or obese 11. They found that the participants had a significant reduction in body weight, waist and hip circumference, and body fat percentage, as well as a significant reduction in systolic blood pressure. They also found that the women improved their mood and reduced cravings for savoury foods while participating in the study and were found to have improved levels of healthy gut bacteria. Interactions and contradictions when taking Glucomannan Supplements As a dietary supplement, Glucomannan konjac is used as a dietary fibre supplement, most popularly for weight management. 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. Jamilian M, Zadeh Modarres S, Amiri Siavashani M, et al. The influences of chromium supplementation on glycemic control, markers of cardio-metabolic risk, and oxidative stress in infertile polycystic ovary syndrome women candidate for in vitro fertilization: A randomized, double-blind, placebo-controlled trial. Biol Trace Elem Res. 2018;185(1):48-55. doi:10.1007/s12011-017-1236-3