Glucomannan, a type of water-soluble dietary fiber from the root of the konjac plant, may reduce risk factors in people with metabolic syndrome. A double-blind trial found that 8–13 grams per day of glucomannan improved cholesterol levels and blood glucose control in people with metabolic syndrome.¹ It is thought to work in part by acting as a prebiotic fiber, enhancing colonies of beneficial gut bacteria that participate in regulating metabolism.² Even in patients with type 2 diabetes, 3 grams of glucomannan per day for four weeks improved blood glucose control and lipid metabolism compared to placebo.³

Glucomannan is a water-soluble dietary fiber derived from konjac root (Amorphophallus konjac) that delays stomach emptying, leading to a more gradual carbohydrate digestion and glucose absorption. Supplementing with glucomannan before eating has been shown reduce the post-meal elevation of blood glucose levels and long-term supplementation is associated with better blood glucose control and improvements in LDL-cholesterol levels in people with type 2 diabetes.^4,5,6 Research in animals suggests glucomannan may be helpful in managing diabetes-related kidney dysfunction.⁷ Doses between 1 and 10 grams of glucomannan per day have demonstrated efficacy in clinical research.

 

Glucomannan is a water-soluble dietary fiber that is derived from konjac root (Amorphophallus konjac). In a preliminary trial,⁸ addition of either 2.6 or 5.2 grams of glucomannan to a meal prevented hypoglycemia in adults with previous stomach surgery. A trial of glucomannan in children with hypoglycemia due to a condition known as “dumping syndrome” produced inconsistent results.⁹

Glucomannan is a water-soluble dietary fiber derived from konjac root (Amorphophallus konjac). Glucomannan delays stomach emptying, leading to a more gradual rise in glucose levels after eating carbohydrates. This could result in reduced need for insulin after meals in people with type 1 diabetes. In addition, glucomannan has positive effects on carbohydrate and fat metabolism, as well as the gut microbiota.^10,11 These properties could lead to benefits in people with type 1 diabetes, but no research has been done to test this possibility.

Glucomannan is a viscous, soluble dietary fiber that is derived from konjac root. Clinical trials have shown glucomannan has positive impacts on glucose and lipid metabolism.¹² A meta-analysis of 12 randomized controlled trials including 370 participants found that supplementing with 3 grams of glucomannan daily for three weeks or longer reduced LDL-cholesterol levels by 10% and non-HDL-cholesterol levels by 7%.¹³

 

Glucomannan is a water-soluble dietary fiber that is derived from konjac root. Like other sources of fiber, such as psyllium and fenugreek, glucomannan is considered a bulk-forming laxative. A preliminary trial¹⁴ and several double-blind trials^15,16,17,18 have found glucomannan to be an effective treatment for constipation. The amount of glucomannan shown to be effective as a laxative is 3 to 4 grams per day. In constipated people, glucomannan and other bulk-forming laxatives generally help produce a bowel movement within 12 to 24 hours.

 

Glucomannan is a water-soluble dietary fiber that is derived from konjac root (Amorphophallus konjac). A preliminary clinical trial found that approximately one-third to one half of people with diverticular disease had reduced symptoms of diverticular disease after taking glucommanan.¹⁹ The amount of glucomannan shown to be effective as a laxative is 3–4 grams per day.

Glucomannan is a viscous soluble fiber from konjac root that has demonstrated multiple positive effects on metabolic health, including lowering cholesterol, triglyceride, and blood glucose levels.^20,21 Studies examining its possible role as a weight loss aid, however, have had mixed results. One placebo-controlled trial in 20 participants with obesity found taking 1 gram of glucomannan three times daily at mealtimes for eight weeks, while making no other changes, led to a weight loss of 5.5 pounds.²² However, an eight-week placebo-controlled trial in 53 adults with overweight and obesity found 1.33 grams of glucomannan three times daily with meals did not impact weight loss.²³ A meta-analysis of findings from eight randomized controlled trials did not find a significant effect of glucomannan on weight loss in people with overweight and obesity.²⁴

 

Increased fiber intake is thought to have potential benefit in a weight-loss program since dietary fiber dilutes calories, slows down the eating process, and may make people feel more full despite eating fewer calories.²⁵ However, research on using fiber in the treatment of childhood obesity has focused on using fiber supplements rather than comparing low- and high-fiber diets. Supplementation for four months with 2 to 3 grams per day of a bulking agent called glucomannan, was effective in a group of obese adolescents in one controlled trial,²⁶ but another controlled trial found no significant effect of 2 grams per day for two months.²⁷