General Description
Glucomannan is an unabsorbable polysaccharide composed of the simple
sugars glucose and mannose. It occurs as a natural dietary fiber
in tubers from certain species of the plant genus Amorphophallus,
which grow in tropical and subtropical regions of Asia. Although
at least five Amorphophallus species are known to produce glucomannan,1
most of what is used commercially is derived from the konjac plant,
Amorphophallus konjac, which is why the fiber is commonly called
konjac glucommanan or konjac mannan. Recently gaining popularity
as a dietary fiber supplement, glucomannan has stronger gel-forming
properties than pectin or guar gum, and has the advantage of being
tasteless and easy to swallow.
Health Applications
- Weight loss
- High cholesterol
- Diabetes
- Constipation/colon health
Primary Uses
Glucomannan is often used as a weight-loss product, and preliminary
research indicates it may be helpful in this area. Studies conducted
on obese subjects indicate that glucomannan may help reduce weight,
lower cholesterol and triglyceride levels, and improve glucose
tolerance.2-5 In two of the studies, glucomannan
was found to reduce hunger by providing a sense of fullness.4,5
Glucomannan's cholesterol-lowering capabilities have been demonstrated
in numerous animal and human studies,6-12
and some research suggests that it may improve glucose tolerance
in diabetic patients as well.10-15 As a good
source of dietary fiber, glucomannan promotes healthy bowel function,
and it has been shown to be effective for treating constipation
in clinical trials.16-19
Dosage/Toxicity
Dosage recommendations for glucomannan vary with intended use.
Some studies on glucose tolerance and cholesterol control have
used as much as 13 grams per day.11 Most studies
on constipation have used three grams per day;16-19
however, one study found four grams per day to be more effective.17
Although glucomannan has no known toxicity and has not been associated
with any negative side effects, research indicates that it may
interfere with the absorption of some fat-soluble vitamins;20
thus, multivitamin supplements may be advisable for long-term
glucomannan users. |
