Colonic flatulence
Lactose that has not been metabolised reaches the large intestine, where it encounters gut microflora consisting of a number of lactose-fermenting bacteria, but there is no absorption system for carbohydrates in the large intestine. As long as lactose remains in the colon, abdominal discomfort will persist. Lactose is fermented by gut microorganisms to produce hydrogen, carbon dioxide, methane gas, and a few fatty acids. Bacteria obtain their energy needs from fatty acids. The gas accumulates and eventually occupies the colon, causing flatulence. The microflora’s ability to ferment lactose varies from person to person; consequently, the severity of flatulence may differ from person to person.
