What is lactose intolerance?

Lactose intolerance is a disordered utilization of milk sugar (lactose). The intolerance occurs due to a defect or deficiency of the enzyme lactase. If the organism does not have a sufficient amount of lactase to utilize lactose, the two-fold sugar cannot be split. The uncleaved lactose thus reaches the large intestine, where it does not really belong. Consequently, hydrogen, carbon dioxide and short-chain fatty acids are formed in the large intestine.