If your doctor thinks you have lactose intolerance, he or she will ask questions about your medical history and do a physical exam. Before making a diagnosis, your doctor may ask that you avoid dairy products for a short time to see if your symptoms improve. You may also be asked to bring in a sample of your stool. The stool of a person who has lactose intolerance is usually loose or watery. It also can be foamy.
To confirm a diagnosis, your doctor may order a:
- Elimination diet. If an elimination diet is to be used for diagnosing lactose intolerance, it should be a rigorous diet. Elimination of all milk products should eliminate symptoms completely if lactose intolerance alone is the cause of the symptoms.
- Milk challenge. A simpler way of diagnosing lactose intolerance than an elimination diet. A person fasts overnight then drinks a glass of milk in the morning. If a person is lactose intolerant, the milk should produce symptoms within several hours of ingestion.
- Hydrogen breath test. This is the most accurate lactose intolerance test. You will be asked to drink a liquid that contains lactose and then breathe into a machine several times over a couple of hours. If the hydrogen levels in your breath are high, you may have lactose intolerance. This test is not usually done on babies and very young children, because it can cause severe diarrhea.
- Lactose tolerance test. This test measures your blood sugar after you eat or drink lactose. You will drink a liquid that contains lactose, which may cause gas or pain in your belly. Then your blood will be tested every 30 minutes for 2 hours. If your blood sugar levels do not rise, you may be lactose-intolerant.
There’s currently no way to boost your body’s production of lactase, but you can usually avoid the discomfort of lactose intolerance by:
The most obvious means of treating lactose intolerance is by reducing the amount of lactose in the diet. Fortunately, most people who are lactose intolerant can tolerate small or even moderate amounts of lactose. It often takes only elimination of the major milk-containing products to obtain sufficient relief from their symptoms. Thus, it may be necessary to eliminate only milk, yogurt, cottage cheese, and ice cream. Though yogurt contains large amounts of lactose, it often is well-tolerated by lactose intolerant people.
Another means to reduce symptoms of lactose intolerance is to ingest any milk-containing foods during meals. Meals (particularly meals containing fat) reduce the rate at which the stomach empties into the small intestine.
Caplets or tablets of lactase are available to take with milk-containing foods.
Some people find that by slowly increasing the amount of milk or milk-containing products in their diets they are able to tolerate larger amounts of lactose without developing symptoms. This adaptation to increasing amounts of milk is not due to increases in lactase in the intestine. Adaptation probably results from alterations in the bacteria in the colon.
Calcium and vitamin D supplements
It is important for lactose intolerant persons to supplement their diets with calcium. A deficiency of vitamin D also causes disease of the bones and fractures. Milk is fortified with vitamin D and is a major source of vitamin D for many people. Although other sources of vitamin D can substitute for milk, it is a good idea for lactose-intolerant persons to take supplemental vitamin D to prevent vitamin D deficiency.