For nearly 50 million Americans, a glass of milk or slice of cheese can bring on a stomachache, bloating, and diarrhea. These people are lactose intolerant, or unable to digest lactose, a sugar found in dairy foods. Why? The cells that line their small intestines don’t produce sufficient amounts of an enzyme called lactase, which breaks down milk sugar into simpler forms that can be absorbed by the body

As a result, milk products can trigger uncomfortable symptoms, which also include gas, cramps, and nausea. These problems usually start a half hour to 2 hours after eating milk products and can range from mild to severe. Most people who have this condition were born with it; certain ethnic and racial populations are at greater risk. In fact, as many as 75 percent of Jewish, Native American, and Mexican American adults, along with 90 percent of Asian American adults, are lactose intolerant to some degree.

Other people can develop the problem as they age, because the body gradually produces less lactase as you consume fewer dairy products after childhood. An intestinal problem, such as Crohn’s disease or gastroenteritis, may also cause a temporary bout of lactose intolerance, since inflammation may prompt the small intestine to cease lactase production.

Although there are supplements that contain the lactase enzyme, they offer only temporary relief. Fortunately, people who are lactose intolerant can now buy a variety of lactose-free dairy products in the dairy aisles of most grocery stores. Because milk products are a primary source of calcium, experts recommend taking a calcium supplement.

ADDITIONAL FACTS

  1. Babies born prematurely are more likely to be lactose intolerant.
  2. To diagnose lactose intolerance, a physician may perform a hydrogen breath test, a lactose tolerance test, and a stool acidity test.