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Thirty minutes have passed since you ate a bowl of ice cream, and now your stomach is cramping and gassy. You feel like you might have diarrhea. Does this sound like you? Or, you had milk, mashed potatoes, or even candy almost 2 hours ago and have these symptoms. Does that sound like you? If either does, you could have lactose intolerance.

Lactose is the main sugar in milk and most other dairy products. Your small intestine makes the enzyme lactase to help you digest that sugar. When you're lactose intolerant, you don't make enough lactase to digest lactose well.

You can't cure lactose intolerance, but if you change what and how you eat, you may cut or even get rid of your symptoms.

Ease Your Symptoms

Millions of Americans have symptoms of lactose intolerance: 

  • Bloating
  • Cramps
  • Diarrhea
  • Painful gas
  • Nausea

You can use trial and error to find out what foods cause symptoms, and in what amount. Or, you may want to see your doctor for a diagnosis. You may be sensitive to small amounts of foods that have lactose, or you may only have symptoms if you eat a lot of lactose foods. Your symptoms may be severe or mild. Lactose intolerance is different for everyone.

Find the Culprits (Hint: It might not just be dairy.)

Milk and dairy products are the best-known lactose foods, but there are many others. Some nondairy products have a protein called casein, which can have traces of lactose. To avoid symptoms from lactose intolerance, read food labels carefully. When shopping or cooking, look for these ingredients that have lactose: 

  • Curds
  • Dry milk solids
  • Milk
  • Milk byproducts
  • Dry milk powder
  • Whey

If you are highly sensitive to lactose, you may need to avoid foods such as: 

  • Baked goods
  • Bread, baking, and pancake mixes
  • Breakfast cereals
  • Certain types of candy, such as milk chocolate
  • Instant foods (breakfast drink mixes, mashed potatoes, soups, and meal replacement drinks)
  • Margarine
  • Nondairy creamers (liquid and powdered)
  • Nondairy whipped topping
  • Processed meats (bacon, hot dogs, sausage, and lunch meats)
  • Protein and meal replacement bars
  • Salad dressing

Get a Diagnosis

Your doctor may ask you to keep a diary of the foods you eat, to note when you have symptoms, and to stop eating an offending food to see if your symptoms go away. To make a diagnosis, some doctors simply look at your symptoms and whether avoiding dairy products for 2 weeks relieves them.

To confirm the diagnosis, your doctor may do other tests, such as:

  • Hydrogen Breath Test: Normally, people have very little hydrogen in their breath. If your body doesn't digest lactose, though, hydrogen builds in your intestines, and after a while it's in your breath. This test measures how much hydrogen is in your breath after you have a lactose-loaded drink several times in a few hours. If your levels are high 3 to 5 hours later, your body does not digest lactose well.
  • Lactose Tolerance Test:  When your body breaks down lactose, it releases sugar into your blood. This tests how much sugar is in your blood. After you fast, a small sample of blood is taken. Then, you drink a liquid that is high in lactose. Two hours later, you give another blood sample. Because lactose causes blood sugar levels to rise, your blood sugar levels in this sample should be higher. If you're lactose intolerant, you'll have just a low rise in blood sugar and symptoms.