Learn about how to change your diet to help manage your lactose intolerance symptoms and get enough nutrients, and find out about foods that contain lactose. Find out about lactose intolerance, what the symptoms are, what the treatments are, what tests can find out if you have it, and what causes it. Millions of Americans can’t digest a certain sugar in milk and milk products called lactose. If you’re one of them, you have lactose intolerance. The condition isn’t harmful, but it can be. 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. What is lactose intolerance? Lactose intolerance is a common cause of abdominal cramping, bloating, and loose stools. This condition occurs when the body does not have enough of the intestinal enzyme lactase. The job of lactase is to break down lactose, the main sugar in milk. Lactose intolerance is common and can cause a wide range of symptoms. Here are 5 signs and symptoms of lactose intolerance. Lactose intolerance is most common among people of East Asian descent (with 90% lactose intolerance), people of Jewish descent, people in African and Arab countries, and among some people of Southern European descent. Lactose intolerance occurs in people who lack the enzyme they need to break down lactose, the sugar in milk. It causes digestive distress when you eat dairy products. Can adults become lactose intolerant? This article breaks down what symptoms to look for, how this condition is diagnosed and available symptom support options. Lactose intolerance occurs when your body is unable to digest the sugar lactose, which is found in milk and milk products.