Lactose intolerance is a common digestive problem where the body is unable to digest lactose. Lactose is a type of sugar, found in milk and dairy products. In the body, it is broken down by an enzyme called lactase. In cases of lactose intolerance, the body does not produce enough lactase meaning lactose is not fully digested. Lactose intolerance generally manifests as abdominal pain, gas, and diarrhea following ingestion of dairy sources such as whey protein. Most people with lactose intolerance can still consume small amounts of lactose with no ill-effects. There are therefore several options available to those looking for a quality protein intake, but trying to avoid the symptoms of lactose intolerance.