The hemicellulose component of dietary fiber.

The digestion of hemicellulose in humans was investigated with subjects with an ileostomy and subjects with healthy small and large bowel on a fixed diet of known fiber content. It was shown that an average of 65% of the hemicelluloses were digested by women ileostomy subjects and 83% by men ileostomy subjects and 97% in the intact women subjects and 95% in the intact men subjects. The monosaccharide composition of the hemicelluloses in the diet, small bowel excreta and feces, suggest that an arabinoxylan hemicellulose from cereals, is not digested in the small bowel and only partly digested in the large bowel. This study suggests that it is the arabinoxylans from cereals that are important components of dietary fiber.