Lactose intolerance is the condition in which lactase, an enzyme needed for proper metabolization of lactose (a constituent of milk and other dairy products), is not produced in adulthood. A lactose tolerance test, a hydrogen breath test, or a stool acidity test is required for a clinical diagnosis [1]. With lactose intolerance, the result of consuming too much lactose is excess gas production and often diarrhea. Lactose-intolerant adults can drink about 250 ml (8 oz) of milk per day withou ...
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Signs and symptoms
... The signs and symptoms of lactose intolerance usually begin 30 minutes to two hours after eating or drinking foods that contain lactose. Common signs and symptoms include: Nausea Abdominal cramps Bloa...
Source: MayoClinic

... The cells that line your small intestine produce an enzyme called lactase. This enzyme is responsible for breaking down lactose into two simple sugars — glucose and galactose — that can be...
Source: MayoClinic

Risk factors
... A few risk factors can make you or your child more prone to lactose intolerance: Age. Many adults have some degree of lactose intolerance by age 20. However, the condition is uncommon in babies and yo...
Source: MayoClinic

When to seek medical advice
... If you have signs and symptoms of lactose intolerance, talk to your doctor. Too many people diagnose themselves with lactose intolerance, without considering that their symptoms could be a sign of a m...
Source: MayoClinic

Screening and diagnosis
... Your doctor may diagnose lactose intolerance based on your symptoms and your response to reducing the amount of dairy foods in your diet. Your doctor can confirm the diagnosis by conducting one or mor...
Source: MayoClinic