Lactose malabsorption and postgastrectomy milk intolerance, dumping, and diarrhoea.

In patients with deficient intestinal lactase activity there is decreased hydrolysis of ingested lactose into its constituent monosaccharides glucose and galactose, and abdominal distension, cramps, and diarrhoea may occur after the consumption of lactose-containing foods. Unhydrolysed lactose within the lumen of the small intestine has been shown to exert an osmotic effect and this can be demonstrated radiologically to result in small intestinal distension, dilution of contrast medium, and rapid transit of intestinal contents along the gut (Laws and Neale, 1966). There are a number of reports of patients developing milk intolerance and symptoms of lactose intolerance after gastric surgery (Auricchio, Rubino, Landolt, Semenza, and Prader, 1963; Hooft, van Hauwaert, de Lacy, and Adriaenssens, 1963), and it has been suggested that intestinal lactase activity decreases following partial gastrectomy and gastrojejunosotomy of the Billroth II type (Gryboski, Thayer, Gryboski, Gabrielson, and Spiro, 1963). It is possible that the clinical symptoms of postgastric milk intolerance, dumping, and diarrhoea might be explained by decreased intestinal lactase activity, and in order to examine such a possibility the relationship of these syndromes to lactose malabsorption was investigated in 50 patients, who, having undergone either partial gastrectomy or vagotomy with drainage, developed various combinations of milk intolerance, dumping, and diarrhoea.