why are some persons lactose intolerance

Lactose is a type of sugar that is present in milk. Lactose is digested in the intestine by an enzyme. The levels of this enzyme are high in infancy especially when the baby is being breastfed.

After weaning, the levels of this enzyme decrease. In some people, the levels of this enzyme are so low that even small amounts of lactose cannot be digested. This undigested lactose is broken down by the intestinal bacteria giving rise to gas. This gas is what causes the bloating sensation in lactose intolerance. Some people are more susceptible to this while others do not suffer from this at all. The only way to treat this is to completely exclude or reduce lactose from the diet.