For weight loss and appetite suppression
A number of placebo-controlled studies have shown that relatively small amounts of glucomannan (1-4 grams a day) enhance weight loss. In one randomized, double-blind, placebo-controlled trial, subjects were assigned to consume 1 gram of glucomannan with 8 ounces of water one hour before breakfast, lunch and dinner and not to change their eating or exercise patterns. Subjects in the glucomannan group lost 5.5 pounds, whereas the placebo group gained 1.5 pounds after 8 weeks.
The beneficial effects of glucomannan on weight loss do not appear to be dependent on the caloric content or distribution of the diet, which makes this supplement extremely versatile for a wide range of people consuming any diet (very low-carbohydrate, low-fat, high-protein, etc.).
Glucomannan works primarily by reducing appetite because of its powerful bulk-forming properties in the stomach. This in turn promotes a feeling of fullness and passively reduces the total amount of calories consumed.
Controlling glucose and insulin surges
The bulk-forming properties of glucomannan delays the rate by which food exits the stomach and enters into the intestines for absorption. This reduces the rate of absorption of nutrients into the bloodstream and has tremendous health implications due in part to better control of glucose and insulin surges.
A large number of studies have consistently shown that glucomannan taken prior to or with a meal significantly reduces the glucose and insulin response by as much as one-half. In other words, glucomannan effectively reduces the glycemic index of foods and meals and a large number of well-controlled studies have shown that high glycemic index diets are associated with increased risk for heart disease and diabetes.
Thus, the simple addition of glucomannan to a meal would be predicted to have significant clinical benefits on risk of chronic disease, in particular those related to insulin resistance and diabetes.
In addition to its affect on weight loss, and glucose and insulin levels, glucomannan has been shown to have significant and consistent cholesterol-lowering effects in a large number of clinical studies. The effects are potent even with small doses (less than 4 grams a day). For example, in a randomized, placebo-controlled, double-blind, cross-over clinical trial in diabetic subjects, 3.6 grams of glucomannan per day decreased LDL-cholesterol by 21%, improved the total cholesterol to HDL-cholesterol ratio by 16%, and decreased the fasting and 2-hour glucose levels by 23% and 28%, respectively.
In summary, glucomannan is a highly viscous soluble fiber that has been widely used in the orient for hundreds of years. An impressive amount of research has shown that small amounts of glucomannan taken before or during meals leads to significant weight loss and consistent reductions in appetite, cholesterol, glucose, and insulin. These effects have been observed in a variety of healthy and clinical populations.
Athough glucomannan has been shown to effectively enhance weight loss, the beneficial effects of its lipid-lowering properties and its effects on glucose and insulin are not dependent on losing weight. Thus the therapeutic applications of glucomannan extend well beyond weight loss to include individuals with glucose and insulin disturbances (e.g., insulin resistance, glucose intolerance, and type II diabetes), cholesterol and other lipid disorders, and those with combinations of these disorders such as metabolic syndrome.
Given the epidemic prevalence of obesity, cardiovascular disease, and diabetes, the potential value of glucomannan as a preventive and therapeutic adjunct to other lifestyle interventions (i.e., diet and exercise) is enormous. The value of soluble fibers in the diet for promoting health is without debate, and glucomannan beats them all.