Lactose intolerance occurs due to decreased production of the lactase enzyme. Undigested lactose builds up in the large intestine, resulting in the growth of gas-producing gut bacteria, which contribute to the symptoms of lactose intolerance, including bloating, flatulence, diarrhea, nausea and abdominal pain. This may be a temporary lactase reduction (e.g. after surgery or short-term illness) or a permanent reduction, due to a lifelong disease (e.g. cystic fibrosis) or due to genetic variation.
Our DNA Lactose Intolerance Test identifies individuals that carry a genetic variation that permanently reduces lactase production. Lactose intolerance differs from a dairy allergy, as individuals who are allergic to dairy will have an immune response (an allergic reaction) against milk proteins, whereas lactose intolerance is a digestive disorder.