Ans. is 'd' i.e., All of the above Dietary fibre Dietary fibre consists of unabsorbable cell wall and other constitutents of vegetable food like cellulose, lignin, hemicellulose, gums, pectins, glycoproteins and other polysaccharides. Dietary fibre absorbs water in the intestine, swells, increase bulk of stood by increasing water content of faeces and soften it, decreases transit time by facilitating colonic transit. "The presence of fibre shoens the transit times and increases the stool bulk" Dietary fibre is of two types: Soluble fibres: It absorbs upto 15 times its weight in water as it moves through GIT, producing softer stools. Its good sources are oat, flaxseeds, peas, beans, apple, citrus fruits, carrots, barley and psyllium. Insoluble fibre: It promotes movement of material through digestive system and increases stool bulk. Its good sources are wheat flour, wheat bran, nuts and vegetables. Advantages of fibres Dietry fibre contribute bulk by absorbing water 1-15 times of its own weight and thus hastens the passage through the gut, decreasing the transient time. By increasing the bulk, it provides a larger volume of indigestible material to colon. Dietary fibre is known to be associated with reduced incidence of coronary aery diseases. The mechanism of its action is attributed to its binding to bile salts and preventing its absorption and thus reducing cholesterol (LDL cholesterol) level in circulation. The fibre, paicularly the gum and pectin, when ingested with a diet, are repoed to reduce post-prandial glucose level in blood - helpful in DM. Dietary fibre reduce the incidence of diveiculitis, constipation, hemorrhoids, irritable bowel syndrome and colon cancer.