Meteorism, flatulence, swelling, abdominal pain, diarrhea or constipation are the main symptoms of lactose intolerance – explains Dr. Beatrice Salvioli, gastroenterologist at Humanitas. However, they can change a lot from subject to subject because they depend on the severity of the intolerance and the type of meal ingested. This means that some intolerant individuals may take limited doses of lactose without any side effects. Other symptoms of intolerance may be nausea, headache, exhaustion and rashes. In fact, there are various degrees of lactose intolerance that depend on the extent of enzyme deficiency. In the specific, the lactase enzyme present in the small intestine has the task of separating, that is, decomposing, the lactose into the two simple sugars which compose it, galactose and glucose. This division takes place in the small intestine by the enzyme lactase and if the lactose, like any other undigested food residue, remains in the intestinal tract it is fermented by the bacterial flora. The most common diagnostic test for possible lactose malabsorption (and therefore the absence of the enzyme) is the breath test, a non-invasive test that consists of the analysis of the air exhaled by the subject before and after administration of a dose of lactose. When the milk sugar is not digested and starts to ferment, there is an overproduction of hydrogen and the test detects if there is malabsorption. A genetic blood test, on the other hand, can detect the possible persistence of the lactase enzyme.
