Coconut kernel is an excellent source of dietary fiber. Coconut fiber is prepared from finely ground, dried and defatted coconut kernel. Coconut fiber has higher dietary fiber content than any other dietary fiber supplements. Dietary fiber from coconut has all the benefits of other dietary fibers. It contains four times as much fiber as oat bran and twice as much fiber as wheat bran or flax seed meal. The chemical composition of Neutral Detergent Fiber (NDF) isolated from coconut kernel contains hemicellulose (45.10 %), cellulose (43.28 %), lignin (8.15 %), cutin (3.28 %), and silica (0.25 %).
Administration of hemicellulose rich coconut fiber caused significant lowering of total cholesterol, triglycerides, and phospholipids in serum and tissues. Rats fed fiber showed an increased concentration of hepatic bile acids, increased faecal excretion of neutral sterols and bile acids. The effect of feeding coconut fiber to rats (25 %) caused a decrease in the levels of serum lipids and increased the lipolysis. Studies showed that feeding coconut fiber exerted significant hypoglycemic action in rats. Also, studies using fiber rich polysaccharide fraction isolated from defatted coconut kernel caused significant antidiabetic, hypolipidemic and antiperoxidative effects in diabetic rats.