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What is Lactose Intolerance?


Lactose is a sugar in dairy products such as cheese or milk. Lactase, an enzyme in the intestines, digests lactose. Without enough lactase, lactose intolerance can occur. Lactose intolerance is common, and anyone can have it. Almost half of all babies with persistent diarrhea have it.


What Causes Lactose Intolerance?


Cells that make lactase enzyme can be damaged by injury or diseases, and then don’t make enough lactase. Rarely, children are born with a lactase enzyme deficiency and cannot make lactase.


What are the Symptoms of Lactose Intolerance?


Most symptoms occur within 30 minutes to 2 hours after eating milk products. They include stomach pain and cramps, bloating, nausea, diarrhea, gas, feeling sick, and rumbling sounds in the abdomen.


How is Lactose Intolerance Diagnosed?


The doctor will take a medical history and do a physical examination. Tests are done to measure absorption of lactose in the digestive tract. These tests are the lactose tolerance test, hydrogen lactose breath test (most accurate test), and stool acidity test (for children). Rarely, a small tissue sample (biopsy) may need to be taken from the intestine for study when the diagnosis is not clear.


How is Lactose Intolerance Treated?


Babies and young children shouldn’t have foods containing lactose. Older children and adults usually don’t have to avoid lactose completely but should figure out the amount that they can have, based on symptoms after ingestion of lactose. Calcium and Vitamin D pills may be needed to replace what would normally be obtained from milk. Calcium is very important for children, teenagers, and pregnant, breast feeding, and post-menopausal women. Instead of calcium pills, eating more calcium-rich foods, such as shrimps, broccoli, and leafy green vegetables, is possible. Over-the-counter lactase enzyme supplements (e.g. Lactaid) are available. Probiotics may help as well. Symptoms take about 3 weeks to go away once eating dairy products stops.


Dos and DON’Ts in Managing Lactose Intolerance:



  • DO get enough calcium and vitamin D, from diet or supplements. Read food labels to see whether food contains lactose or has too much vitamin D and calcium.

  • DO tell your doctor about all your medications. Some contain lactose.

  • DO call your doctor if a milk-free diet doesn’t help symptoms.

  • DON’T eat foods that may contain hidden lactose. These foods include bread and baked goods, processed breakfast cereals, instant potatoes, soups, breakfast drinks, margarine, lunch meats, salad dressings, candies, and mixes for pancakes, biscuits, and cookies.

  • DON’T take medications that contain lactose as a base (e.g. Birth Control Pills, Pepcid AC, etc.).

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