Described are a number of compositions, namely a konjac mannan mixture, a ginseng composition, and a composition comprising konjac mannan and American ginseng. Methods of use of these compositions are described including their use for reducing blood glucose in non-diabetic and diabetic individuals, as well as reducing postprandial blood glucose in such individuals. Applications in the treatment of hyperlipidemia, high blood pressure, an increase in nitric oxide, Syndrome X and cardiovascular disease are also described. Various other applications of the compositions and methods are also described.