Hypocholesterolemic effect of blue-green alga, ishikurage (Nostoc commune) in rats fed atherogenic diet

Blue-green alga, Nostoc commune is rich in dietary fiber. To examine the hypocholesterolemic effect, the alga or the dietary fibers were given to the rats fed cholesterol diet. Serum cholesterol elevation was significantly depressed in those rats. Cholesterol increased in the liver of rats given the alga and the fiber. The content of fecal cholesterol and bile acid unchanged. Of the dietary fibers, oxalate-oxalic acid soluble substance (OOSS) found abundant in the alga was most effective in lowering cholesterol in the serum. It seems to depress the elevation of LDL-cholesterol. The mechanism of hypocholesterolemic effect by OOSS remains to be unclear. This study indicated that Nostoc commune is expected to be a new dietary fiber source of possible importance in human nutrition.