Sugar-induced diarrhoea in children.

In recent years there has been a proliferation of knowledge about normal and abnormal digestion and absorption of carbohydrates. Many of these advances have been made since Anderson's comments about sugar intolerance in her review of intestinal malabsorption in childhood published in this journal in 1966, and since Holzel's review of the problem in 1967. This review is not intended as a comprehensive survey of the vast literature on this topic, but is an attempt to summarize current knowledge of disorders of carbohydrate digestion and absorption in children. Practical rather than theoretical aspects will be emphasized. Application of this knowledge promises to be of great benefit to children throughout the world because these disorders are common and potentially lethal, but eminently treatable. Carbohydrates are of universal dietary importance since they supply about one-half of man's caloric needs. In poorer communities they constitute an even larger proportion of the diet. The major dietary carbohydrates, starch, lactose, and sucrose, are consumed in varying proportions according to custom and age. Lactose is, of course, relatively more important in infants and young children. In health, starch is hydrolysed in the lumen of the gut by amylases to maltose (a disaccharide), maltotriose (a trisaccharide), and limit dextrins (oligosaccharides). As pointed out by Gray (1970) this is contrary to the still widely held notion that disaccharides and monosaccharides are the final products of the hydrolysis of starch. The hydrolytic products of starch digestion are then presented to the small intestinal epithelium where mucosal disaccharidases split them further to the monosaccharides glucose, galactose, and fructose. Glucose and galactose are then transported through the epithelial cell by an energyand sodiumdependent active transport process. This has been reviewed by Crane (1968). It has been