Foods to Avoid Before a Lactose Intolerance Test

Lactose intolerance is a digestive condition in which affected people are unable to break down lactose, which is the sugar in milk. The disorder is due to an insufficient amount of lactase enzymes. Lactase metabolizes lactose within the small intestine. Lactose intolerance is diagnosed most accurately through tests that are conducted after a fasting period of 12 to 24 hours. Foods, drinks and medications can affect lactose test results, leading to inaccurate readings.

• Lactose testing can be offset by dairy consumption.

Identification

• Symptoms of lactose intolerance begin within 30 minutes of consuming a dairy product, with milk typically producing more pronounced symptoms than foods that have been manufactured and processed such as yogurt and cheese. Lactose intolerance causes gastrointestinal reactions of stomachache, cramping, flatulence, burping, bloating, nausea, vomiting and diarrhea. Those symptoms may lead to fatigue and irritability due to prolonged discomfort. Consulting with doctors about lactose intolerance symptoms leads to lactose intolerance testing, diagnosis and treatment through dietary changes.

Function

• The hydrogen breath test calculates the amount of hydrogen in the breath produced by undigested lactose. The test is conducted by blowing into a tube for an initial hydrogen sample. Then a food or beverage containing lactose is consumed, with a second breath test taken 30 minutes later. An increase in hydrogen levels on the second sample indicates potential lactose intolerance. A lactose tolerance test measures how well the body responds to ingested liquid containing lactose over a two-hour period.

Significance

• Testing for lactose typically requires fasting for 12 to 24 hours, meaning no food or drink for that period. Consuming dairy products such as yogurt, cheese, milk and ice cream within 48 hours of a lactose test may produce inaccurate results. Eating a food that contains lactose can produce intolerant symptoms the first day. There may be no symptoms the next day when lactose is consumed, as the body has built up a defense of enzymes due to the first consumption.

Types

• Low-lactose dairy products, lactose-reduced milk or cheeses, soy-based products and rice milk work in the same manner as dairy products in regard to testing. While less lactose may not affect the results as much as high-lactose content in the digestive system, accurate results can still be hindered. Processed foods often contain lactose. Such foods should be eliminated from a diet prior to testing for lactose intolerance.

Considerations

• Hidden sources of lactose are in an array of foods which should be eliminated from an individual's diet 48 hours before lactose tests are conducted. Foods that contain lactose-based ingredients include baked goods, breads, instant potatoes and soups, butter, margarine, sour cream, protein bars, chocolate, candy, processed meats, snack foods, salad dressings, gravy, frosting, pudding, coffee creamers and whipped creams. Some medications such as birth control pills and treatments for stomach and gas indigestion contain lactose and should be avoided prior to testing. Consult with a doctor before discontinuing medications.