Glucomannan root supplement, does this fiber help with weight loss? Side effects, health benefit
January 2 2017 by
Ray Sahelian, M.D.

Glucomannan is a dietary fiber becoming more popular in Western countries. Peoples in East Asia have used this fiber for more than a thousand years. This dietary fiber is the main polysaccharide obtained from the tubers of the Amorphophallus konjac plant. Glucomannan fiber has a extraordinarily high water holding capacity, forming highly viscous solutions when dissolved in water. It has the highest molecular weight and viscosity of any known dietary fiber. This supplement has studied in the treatment of obesity due to the satiety sensation that it produces; as a remedy for constipation, because it increases the feces volume; as a blood cholesterol lowering agent, interfering in the transport of cholesterol and of bile acids and as blood sugar lowering supplement for those with diabetes. The use of a glucomanna supplement delays gastric emptying and slows glucose delivery to the intestinal mucosa.
   If you would like to eat less, consider Diet Rx natural weight control product and get a free bottle. See below for details. In November 2010, Dr. Mehmet Oz, of the Oz show health program on TV, mentioned glucomannan as his best diet pill source. I am not sure it is the best, but this substance has many health benefits.

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Glucomannan 500 mg, 90 capsules




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The newsletter reviews the latest research on weight loss, cholesterol management, and overall health research
Buy Glucomannan capsules or Diet Rx as an effective weight management supplement
Glucomannan root has the ability to absorb up to 50 times its weight in water.

Glucomannan root and cholesterol
It appears that it may be a natural herb for cholesterol management in adults and children.

Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis.
Am J Clin Nutr. 2008.
The objective was to perform a meta-analysis of randomized controlled trials of glucomannan to better characterize its impact on plasma lipids, fasting blood glucose, body weight, and blood pressure. Glucomannan appears to beneficially affect total cholesterol, LDL cholesterol, triglycerides, body weight, and fasting blood glucose, but not HDL cholesterol or BP.

Effect of plant sterols and glucomannan on lipids in individuals with and without type II diabetes.
Eur J Clin Nutr. 2006.
Subjects were supplemented with plant sterols (1.8 g/day), glucomannan (10 g/day), a combination of glucomannan fiber and plant sterols, and a placebo, provided in the form of bars. Overall plasma cholesterol concentrations were lower after combination treatment compared to control. Plasma low-density lipoprotein (LDL) cholesterol concentrations were decreased after glucomannan and combination treatments compared to control. The results suggest that glucomannan fiber and a combination of glucomannan and plant sterols substantially improves plasma LDL cholesterol concentrations.

Konjac glucomannan supplement alleviated hypercholesterolemia and hyperglycemia in type 2 diabetic subjects--a randomized double-blind trial.
J Am Coll Nutr. 2003.
The present study was designed to evaluate effects of konjac glucomannan supplement (3.6 g/day) for 28 days on blood lipid and glucose levels in hyperlipidemic type 2 diabetic patients and the possible mechanism for the reductions in blood lipid levels. Twenty-two diabetic subjects with elevated blood cholesterol levels, but currently not taking lipid-lowering medication, were recruited to participate in a two 28-day period, randomized, double-blind, crossover clinical trial. Compared with placebo, konjac glucomannan effectively reduced plasma cholesterol, LDL-cholesterol, total/HDL cholesterol ratio, ApoB and fasting glucose. The supplement improved blood lipid levels by enhancing fecal excretion of neutral sterol and bile acid and alleviated the elevated glucose levels in diabetic subjects.

Effect of dietary supplementation with glucomannan fiber on plasma total cholesterol and low density lipoprotein cholesterol in hypercholesterolemic children.
Nutr Metab Cardiovasc Dis. 2005.
This paper evaluates the effect of the adjunct of the hydrosoluble fiber glucomannan to a Step-One-Diet in 40 children with high cholesterol, during a randomized controlled trial, to reduce plasma cholesterol. Glucomannan treated group showed decreased values in plasma total cholesterol and low density lipoprotein cholesterol vs. control group after 8 weeks of treatment. These results suggest that this plant fiber may represent a rationale adjunct to diet therapy in primary prevention in high risk hypercholesterolemic children.

PCOS patients
Minerva Ginecol. 2014. Combination inositol and glucomannan in PCOS patients. Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies of the reproductive age in women. PCOS is an endocrine-metabolic disorder characterized by insulin resistance. Aim of the study was to evaluate the efficacy of natural substances such as inositol and glucomannan, and their combination in reducing glucose levels and improving insulin sensitivity in PCOS patients. Forty women with clinical and endocrinological signs of PCOS were enrolled in the study and divided into three groups, including ten women each. The three groups were respectively treated with the combination inositol and glucomannan (A group), inositol (B group), glucomannan (C group) for a period of 3 months. Plasma levels of glucose and insulin were evaluated before and after treatment in our laboratory. There was a reduction in blood glucose and insulin levels, with particular significance in the group treated with the combination of inositol-glucomannan. Present results show that the association-inositol glucomannan may represent a good therapeutic strategy in the treatment of PCOS women with insulin resistance.

Glucomannan and weight loss
Many weight loss products contain this fiber but the results of studies are not conclusive. In otherwise healthy overweight or obese adults, there is some evidence that in the short term this fiber may help to reduce body weight. Data in children are too limited to draw any conclusions.

J Am Coll Nutr. 2015. Konjac Glucomannan Dietary Supplementation Causes Significant Fat Loss in Compliant Overweight Adults. Changes in body composition and blood chemistries between overweight adult subjects receiving a supplement containing either 3 g of konjac glucomannan/300 mg calcium carbonate or a placebo containing only 300 mg of calcium carbonate were compared as the primary objective. A secondary objective was to compare outcome differences between compliant and partially compliant subjects. A total of 83 overweight adults (66 women and 17 men) completed a randomized, double-blind, placebo-controlled protocol in which they received either a glucomannan or placebo supplement for 60 days. Dual-energy x-ray absorptiometry (DEXA) total body scans and a 42-measurement blood test were completed at baseline and 60 days later. Compliance was assessed by rating self-reports of (1) how many tablets were taken, (2) adherence to taking the tablets 30 minutes before eating. An anonymous poststudy questionnaire and telephone calls were also completed by 80 (96%) of the participants who were used as the study cohort. No statistically significant differences were found between the groups on changes from baseline on the DEXA and blood tests. However, when subjects were classified as either compliant or partially compliant using the compliance measures, statistically significant reductions in scale weight, percentage body fat, fat mass, total cholesterol, and low-density lipoprotein (LDL) cholesterol were found in the glucomannan group compared to the placebo group. This study supports the efficacy glucomannan supplementation to reduce body weight, body fat, and circulating cholesterol levels without the concomitant loss of lean mass and bone density often associated with weight loss. However, these positive outcomes were not observable until corrections for compliance were applied.

J Am Coll Nutr. 2014. The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials. The evidence from available RCTs does not show that glucomannan intake generates statistically significant weight loss.

J Obes. 2013. Safety and efficacy of glucomannan for weight loss in overweight and moderately obese adults. Few safe and effective dietary supplements are available to promote weight loss. We evaluated the safety and efficacy of glucomannan, a water-soluble fiber supplement, for achieving weight loss in overweight and moderately obese individuals consuming self-selected diets. Methods. Participants were randomly assigned to take 1.33 grams of glucomannan or identically looking placebo capsules with 236 mL (8 ounces) of water one hour before breakfast, lunch, and dinner for 8 weeks. The primary efficacy outcome was change in body weight after 8 weeks. Other efficacy outcomes were changes in body composition, hunger/fullness, and lipid and glucose concentrations. Safety outcomes included gastrointestinal symptoms/tolerance and serum liver enzymes and creatinine levels. Results. A total of 53 participants (18-65 years of age; BMI 25-35 kg/m(2)) were enrolled and randomized. The two groups did not differ with respect to baseline characteristics and compliance with the study supplement. At 8 weeks, there was no significant difference between the glucomannan and placebo groups in amount of weight loss or other efficacy outcomes or in any of the safety outcomes. Glucomannan supplements administered over 8 weeks were well tolerated but did not promote weight loss or significantly alter body composition, hunger/fullness, or lipid and glucose parameters.

Chronic use of glucomannan in the dietary treatment of severe obesity
Minerva Med. 1992.
Two groups of 25 severely obese patients underwent 3 months of hypocaloric diet therapy either alone or associated with a glucomannan based fibrous diet supplement (approx. 4 grams per day in 3 doses). The diet plus glucomannan group had a more significant weight loss in relation to the fatty mass alone, an overall improvement in lipid status and carbohydrate tolerance, and a greater adherence to the diet in the absence of any relevant side effects.

Breast feeding
I was wondering if is ok for me to take glucomannan fiber now then I'm breastfeeding my 2 months old baby.
   We have no reason to believe that this fiber supplement would have any side effects, but this is something you have to clear with your doctor who can read this page.

Constipation in children
At least one good study shows glucomannan is helpful in relieving childhood constipation.

Fiber is beneficial in the treatment of childhood constipation.
Pediatrics. 2004
We evaluated the effect of fiber glucomannan and placebo in children with chronic functional constipation with and without encopresis in a double-blind, randomized, crossover study. Glucomannan fiber and placebo were given as 100 mg/kg body weight daily (maximal 5 g/day) with 50 mL fluid/500 mg for 4 weeks each. We found it to be beneficial in the treatment of constipation with and without encopresis in children.

Glucomannan side effects, safety, risk, danger
Glucomannan side effects may occur but are minor. If the fiber is used in very high amounts, it may increase the production of flatulence, or cause abdominal pain. High amounts may also modify the bioavailability of other drugs.

The chemical structure consists, mainly, of mannose and glucose in the ratio 8:5 linked by beta (1-->4) glycosidic bonds. Glucomannan is a soluble, fermentable, and highly viscous dietary fiber derived from the root of the elephant yamor konjac plant, native to Asia. It consists of a polysaccharide chain of beta-D-glucose and beta-D-mannose with attached acetyl groups. Human pancreatic and salivary amylase cannot split the beta-1,4 linkages, and hence it reaches the colon without being broken down. In the colon, it is fermented by the bacteria. The molecular weight averages about one million daltons.

Other Products online
Now Foods, Glucomannan, 575 mg, 180 Capsules

Supplement Facts
Serving Size: 3 Capsules
Servings Per Container: 60
  Amount Per Serving % Daily Value
Calories 5  
Total Carbohydrate 2 g <1%*
Dietary Fiber†† 2 g 8%*
Glucomannan (from Konjac Root) (Amorphophallus konjac) 1.725 g (1,725 mg)
* Percent Daily Values are based on a 2,000 calorie diet.
† Daily Value not established.
Fiber is not digested, therefore this product has no caloric effect.

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