Lactose intolerance

Your doctor might suspect 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 more of the following tests:

Hydrogen breath test. After you drink a liquid that contains high levels of lactose, your doctor measures the amount of hydrogen in your breath at regular intervals. Breathing out too much hydrogen indicates that you aren't fully digesting and absorbing lactose.

Lactose tolerance test. Two hours after drinking a liquid that contains high levels of lactose, you'll undergo blood tests to measure the amount of glucose in your bloodstream. If your glucose level doesn't rise, it means your body isn't properly digesting and absorbing the lactose-filled drink.

In people with lactose intolerance caused by an underlying condition, treating the condition might restore the body's ability to digest lactose, although that process can take months. For other causes, you might avoid the discomfort of lactose intolerance by following a low-lactose diet.

To lower the amount of lactose in your diet:

Limit milk and other dairy products

Include small servings of dairy products in your regular meals

Eat and drink lactose-reduced ice cream and milk

Add a liquid or powder lactase enzyme to milk to break down the lactose