|Glucomannan has demonstrated some usefulness in the management of obesity, diabetes and constipation. It has some favorable effects on lipids. Glucomannan is contraindicated in those hypersensitive to any component of a glucomannan-containing product. It is also contraindicated in those with intestinal obstruction, difficulty in swallowing and esophageal narrowing. Glucomannan must be taken with adequate amounts of fluids. Inadequate fluid intake may cause glucomannan to swell and block the throat, esophagus or intestines. Type 2 diabetics who use glucomannan, may require adjustment of their antidiabetic medications. Glucomannan delays stomach emptying, leading to a more gradual absorption of dietary sugar; this effect can reduce the elevation of blood sugar levels that is typical after a meal. Controlled studies have found that after-meal blood sugar levels are lower in people with diabetes given glucomannan in their food, and overall diabetic control is improved with glucomannan-enriched diets according to preliminary and controlled trials. One preliminary report suggested that glucomannan may also be helpful in pregnancy-related diabetes. One double-blind study reported that glucomannan (813 grams per day) stabilized blood sugar in people with the insulin resistance syndrome (syndrome X). In a preliminary study, addition of either 2.6 or 5.2 grams of glucomannan to a meal prevented hypoglycemia in adults with previous stomach surgery; a similar study of children produced inconsistent results. Like other soluble fibers, glucomannan can bind to bile acids in the gut and carry them out of the body in the feces, which requires the body to convert more cholesterol into bile acids. This can result in the lowering of blood cholesterol and other blood fats. Controlled and double-blind studies have shown that supplementation with several grams per day of glucomannan significantly reduced total blood cholesterol, LDL (bad) cholesterol, and triglycerides, and in some cases raised HDL (good) cholesterol. One double-blind study reported that glucomannan (8-13 grams per day) lowered total and LDL cholesterol in people with the insulin resistance syndrome.