Glucomannan is a dietary fiber that comes from the root of the konjac plant. It is used to treat constipation, Type II diabetes, high cholesterol, and obesity. It is also used as a food additive to emulsify and thicken products.

It sells for approximately $20 for a bottle of 180 capsules, and the recommended dosage is 3 capsules per day with a meal.

How It Works

Glucomannan is a popular ingredient in dietary supplements because of its weight-loss and insulin-controlling abilities. Because it is a soluble fiber, it absorbs water to create a gelatinous mass and it helps to slow down the absorption of glucose from the GI tract. This mass may also cause feelings of satiety due to the swelling of the glucomannan in the stomach once it has been mixed with liquids. Consequently, this should suppress appetite and reduce caloric intake.

Scientific Evidence of Effectiveness

A few small, limited studies have shown glucomannan to be an effective weight-loss aid. This effect is believed to be due to a "feeling of fullness" and fecal energy loss. Furthermore, glucomannan has been shown to improve cholesterol and blood sugar levels. However, other studies have shown no such benefits, thus additional research of the safety and effectiveness of glucomannan is needed to determine whether it can help to lower the high prevalence of overweight and obesity.

Side Effects

Glucomannan and glucomannan-containing products have been restricted in several countries because esophageal obstruction has been reported in several people taking glucomannan. Therefore, glucomannan should be avoided by people with a previous history of gastrointestinal obstruction and caution should be used in people with diabetes due to its effects on insulin and blood sugar. Other side effects may include upset stomach, vomiting, diarrhea, and gas.

Sources:

http://www.dietpillguide.info/facts.htm
http://en.wikipedia.org/wiki/Glucomannan
http://www.nextag.com/glucomannan/search-html
http://www.ultimatefatburner.com/propolene-review.html
http://healthlibrary.epnet.com/GetContent.aspx?token=e0498803-7f62-4563-8d47-5fe33da65dd4&chunkiid=21743
http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&uid=16320857&cmd=showdetailview&indexed=google