Excerpted from Gazette Health, 2011, By Laura Evans
An ice cream cone, often viewed as a reward or treat, should be just that. But when the thought of that first bite triggers worries of unpleasant and painful digestive consequences, lactose intolerance may be to blame.
Lactose intolerance is a condition characterized by the inability to fully digest lactose, a sugar found in milk and other dairy products. It results from a deficiency in lactase, an enzyme produced by the cells lining the small intestine that breaks down lactose. “A lactose-tolerant person has lactase in their small intestine that breaks lactose down into small molecules that the person can absorb and digest,” says Michael J. Schwartz, MD, a gastroenterologist at Capital Digestive Care, which has offices throughout Maryland and Washington, D.C. “A lactose intolerant person does not have lactase, so the milk sugar (lactose) cannot be broken down or absorbed. It travels downstream to the colon where bacteria ferment the lactose, producing gas and fluid, which causes gas, bloating, diarrhea.”
Lactose intolerance is a common condition that affects people differently. According to the U.S. National Library of Medicine (NLM), approximately 65 percent of the population has a reduced ability to digest lactose after infancy. The prevalence of lactose intolerance also varies widely by ethnicity. “(We see it) approximately 10 percent (of the time) in adult Caucasians—lower in Northern Europeans than Southern Euroeans; 50 percent in Hispanics; 75 percent in African-Americans; and up to 90 percent in East Asians,” Schwartz says. “This reflects the amount of cow or goat milk in the diet of these ethnic groups during…human evolution.”
The most commonly used tests to diagnose lactose intolerance in adults are a hydrogen breath test and a lactose tolerance blood test. According to NLM, with the hydrogen breath test, the preferred method, patients breathe into a balloon-type container prior to drinking liquid containing lactose. Breath samples are collected at set time periods and the hydrogen level is checked. Normally, very little hydrogen is found in the breath, but if the body has trouble breaking down and absorbing lactose, breath hydrogen levels increase. The lactose tolerance blood test looks for glucose in the blood. For this test, several blood samples will be taken before and after the patient drinks the lactose solution.
“A simple way to diagnose is to stop all dairy products for two weeks and see if symptoms resolve,” Schwartz says. Ceasing or decreasing dairy product intake can also improve the condition. Another option is to take commercially available products containing lactase before eating dairy products, according to Schwartz. Dietary supplements such as Lactaid, Lactrase and Dairy Ease contain lactase to help people better digest dairy products.