Lactose Intolerance Basics

By age 20, approximately 30 million Americans have some sort of lactose intolerance. This condition of the digestive system occurs when people have difficulty digesting lactose, a sugar found in milk and other dairy products.

Symptoms of lactose intolerance include cramps, bloating, gas, diarrhea and nausea. These occur within 30 minutes to two hours after eating dairy products, and the severity varies from mild to severe.