Lactose intolerance—the reduced ability to digest milk sugar (lactose)—is not as hard to cope with as many people think.
Lactose can be digested only with the aid of lactase, an intestinal enzyme that virtually all human infants produce. That’s how babies digest breast milk. Many people, usually those whose ancestors came from northern Europe, around the Mediterranean, and some parts of Africa, manufacture sufficient lactase all their lives. Generally they are the descendants of herders, for whom milk and milk products were staples of the diet.
But the majority of other people gradually lose the ability to make lactase starting at about age two. This is called “lactase nonpersistence” and can lead to lactose intolerance, which is characterized by gas, cramps, bloating, and diarrhea after consuming dairy products. It’s estimated that 15% of white Americans, 70% of black Americans, 90% of Asian Americans, and almost all Native Americans have trouble digesting lactose. People may begin noticing symptoms early or late in life; there is no way to predict when and how much lactase production will be reduced.
Keep these points in mind:
• There are at least two fairly simple tests for lactose intolerance, one a blood test, the other a breath test. A few people have an allergy to milk, which is different from lactose intolerance.
• If you are lactose intolerant, you may still be able to consume some dairy. Studies have shown that most lactose “maldigesters” can drink a cup or two of milk daily without symptoms, particularly if they drink a small amount at a time and drink it with meals. They can also eat ice cream, cheese, and other dairy products in small amounts with other foods. It’s a myth, by the way, that goat’s milk is lactose-free.
• Yogurt usually causes no symptoms. Buy brands with live cultures, since the bacteria help digest lactose.
• Severe lactose intolerance is rare, but people with severe symptoms may need to watch for small amounts of lactose hidden in many foods. Check labels for words like whey, curds, and dry milk solids. A few prescription drugs, including some birth control pills and heartburn drugs, contain tiny amounts of lactose.
• The marketers of lactose-reduced milk have convinced a lot of people that they need these products, which can be expensive. Generic lactase drops, which you add to milk in advance, and lactase pills, taken just before eating dairy, cost less.
• Dairy foods are good sources of calcium, vitamin D, and other nutrients important for health, especially bone health and blood pressure. If you don’t eat any dairy, you will need to make up for shortfalls of these nutrients. Calcium and vitamin D supplements are a good idea for many people, even those who do consume dairy.