Lactose intolerance is a painful & socially difficult condition suffered by between 6 & 10 million people in the UK. Symptoms including nausea stomach cramps bloating gas & diarrhoea are all commonly associated with this condition. What is Lactose Intolerance Lactose & dairy intolerance is the inability to digest significant amounts of lactose the major sugar found in milk. It occurs when there is a shortage of the enzyme lactase produced by the cells lining the small intestine. L