Lactose laxative effect

Lactose has a laxative effect when there is lactose intolerance in the intestinal mucosa (congenital or acquired). It is still not clear whether lactose and lactulose affect the intestinal flora and its metabolism. (Certain quantities of lactose are usually contained as an additive in lactulose syrup ) (164)... 

For patients in whom diarrhea is the primary complaint, avoidance of certain food products may be necessary. Caffeine, alcohol, and artificial sweeteners (sorbitol, fructose, and mannitol) are known to irritate the gut and produce a laxative effect. Lactose... 

The laxative effect of large amounts of lactose in the diets of both mammals and birds has been widely observed. Farmers know that the feeding of large amounts of skim milk or whey to pigs and calves results in a purgative action. This seems to be due principally to the lactose in the milk products. When the lactose level of purified diets was 20, 25, and 30%, transitory symptoms of injury appeared. The symptoms were diarrhea and pot bellies. However, at these levels, growth and food consumption were not affected SO),... 

Various ideas have been considered by which lactose promotes its laxative effect. Perhaps the most probable one is that the sugar acts as a hy-dragog and, as such, results in a water purgation. Possibly this is due to slow hydrolysis and absorption of lactose, thus maintaining a high osmotic pressure in the lumen of the intestines. This increases the water content and distends the intestines which, in turn, stimulates peristaltic action. The subject has been extensively reviewed 34) ... 

Lactulose (4-124) is obtained from lactose by isomerisation in alkaline solutions, where the main structure is -pyranose followed by a-furanose and (S-furanose. Epilactose is formed as a minor product (4-125). Lactulose is an indigestible disaccharide, which is somewhat sweeter than lactose (about 60% of sweetening power of sucrose) and has a weak laxative effect. It stimulates the growth of bifidogenic microflora. 

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