Glucomannan is a water-soluble polysaccharide found in cell walls of some plant species (e.g. Amorphophallus konjac). Its chemical structure is not very complex – it is comprised primarily of a simple chain with a small amount of branching, including β-D-glucose and β-D-mannose residues and acetyl groups. They are combined predominantly by β-1,4 linkages. Amylase found in human saliva cannot cleave them. Because of that, after ingestion, glucomannan reaches the colon almost intact and then is broken down by intestinal bacteria.
Glucomannan has a high molecular weight and strong hygroscopic properties. It is estimated that it has the ability to absorb 50 times its weight in water. It swells up quickly in the body, slows down the absorption of food and gives you a satisfying feeling of fullness. It helps stabilise blood sugar levels and may also contribute to lowering cholesterol concentrations. Like other forms of dietary fibre, it stimulates intestinal motility and promotes bowel movement.
Glucomannan is a popular ingredient of supplements aimed at controlling appetite and reducing body weight.
Dosage: No official guidelines.
The most frequent recommended dosage is 1-5 g once or twice daily, about one hour before a meal.