Particular Type of Fiber Yields Numerous Health Benefits

Dietary fiber is good for health, but many people may be overlooking the most important type. People generally think of fiber as roughage, or insoluble fiber, the indigestible parts of vegetables and fruits that sweep through the gut like a broom. But growing research points to the health benefits of soluble fiber, which forms a gel-like substance when it reacts with water in the gut.

Craig I. Coleman, PhD, of the University of Connecticut School of Pharmacy, Hartford, and his colleagues analyzed 14 studies that used glucomannan, a particular type of soluble fiber, to treat a total of 531 people. Glucomannan comes from the plant Amorpholphallus konjac, and it's sold at most health food stores.

Coleman's review found that daily glucomannan supplements lowered the fasting blood sugar of subjects by an average of 7.4 mg/dl in five weeks. The supplements also led to a 19 mg/dl drop in total cholesterol, a 16 mg/dl decrease in low-density lipoprotein cholesterol, and an 11 mg/dl reduction in triglyceride levels.

Soluble fibers also tend to blunt appetite, and Coleman reported that glucomannan supplements led to an average weight loss of 1.7 pounds over five weeks.

Still other research has found that glucomannan can lower blood pressure and ease constipation.

Reference: Sood N, Baker WL, Coleman CI. "Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis." American Journal of Clinical Nutrition, 2008;88:1167-1175.