A novel use of chitosan as a hypocholesterolemic agent in rats.

A series of experiments with male rats clearly demonstrated the hypocholesterolemic activity of dietary chitosan. On feeding a high cholesterol diet for 20 days, addition of 2 to 5% chitosan resulted in a significant reduction, by 25 to 30%, of plasma cholesterol without influencing food intake and growth. The concentration of liver cholesterol and triglyceride also decreased significantly. Plasma, but not liver cholesterol-lowering effect, was roughly comparable with that of cholestyramine. Chitosan at the 10% level further reduced plasma cholesterol, but depressed growth. Also, finer chitosan particles tended to restrain growth even at the 2% level. In rats fed a cholesterol-free diet containing 0.5% chitosan for 81 days, the concentration of serum cholesterol was the same with that of the corresponding control, but relatively more cholesterol existed as high-density lipiproteins and less as very low-density lipoproteins. Dietary chitosan increased fecal excretion of cholesterol, both exogenous and endogenous, while that of bile acids remained unchanged. There was no constipation or diarrhea. A proper supplementation of chitosan to the diet seemed to be effective in lowering plasma cholesterol.