Lactose is the sugar in diary products. It must be broken down by an enzyme, lactase, before it can be absorbed. This enzyme is produced on the tips of the villi which line the small intestine. When the villi are destroyed, as in celiac disease, lactose from diary products is not absorbed normally. When lactose reaches the colon, bacteria 'eat' the lactose and produce acid and gas.
Water rushes into the intestine to dilute the lactose.
The result is watery, acid diarrhea, bloating, and excessive gas. The recent development of blood tests for the detection and screening of celiacs and their relatives have produced a useful aid to diagnosis and monitoring. Screening at-risk populations to identify biopsy candidates . Providing information to support a diagnosis of GSE . The blood samples required for the tests can be taken at a medical facility and shipped to a lab for processing.