Lactose is a sugar naturally found in dairy products like milk, butter, yogurt, and more. Learn which 5 foods to avoid for lactose intolerance. Lactose is a disaccharide composed of galactose and glucose, which form a β-1→4 glycosidic linkage. Its systematic name is β- D -galactopyranosyl- (1→4)- D -glucose. Find out about lactose intolerance, including symptoms, how it's diagnosed, treatment and what causes it. Lactose is a natural, complex sugar produced in all mammalian milk that’s difficult to breakdown unless you have lactase, a protein, in your small bowel. Lactose intolerance is a condition that makes it hard to digest the sugar in milk and milk products, called lactose. People with lactose intolerance often have diarrhea, gas and bloating after eating or drinking foods containing lactose. Lactose hides in more than just milk. Learn which dairy products, processed foods, drinks, and even medications contain lactose and how to spot it on labels. Lactose is a major disaccharide present in milk. It is composed of two simple sugars, glucose and galactose. Cow, goat, and buffalo milk contains less lactose than human milk. It has several applications in the food industry. Another reason is that lactose intolerance tends to be under-reported: most lactose-intolerant individuals can tolerate at least some lactose before they show symptoms, and their symptoms differ in severity. Lactose is the sugar that’s in milk. Our bodies use an enzyme called lactase to break down that sugar so we can absorb it into our bodies. But people with lactose intolerance don’t have enough. Begin with a lactose-free diet, then gradually reintroduce lactose-containing foods to see how your system responds. Some people with lactose intolerance can tolerate up to 12 grams (g) of lactose at one time, which is a cup of milk or a scoop of ice cream.