A natural sugar, lactose occurs in milk and other dairy products. People who cannot digest the substance often have lactose intolerance, which affects up to 50 million Americans, according to the U.S. Food and Drug Administration. But people with lactose intolerance do not necessarily have to avoid milk. Many can alter their diet to continue enjoying dairy products and consume enough of the nutrients.
Lactase Deficiency
Cells located along the walls of the small intestine create an enzyme known as lactase. The enzyme converts lactose to two types of simpler sugars -- galactose and glucose. Lactose intolerance occurs when the cells in the small intestine stop making sufficient lactase. People with inadequate lactase production have a lactase deficiency, which can lead to an inability to digest lactose properly. The subsequent lactose intolerance emerges in adults more frequently than children.
Lactose Intolerance Symptoms
Lactase deficiency and lactose intolerance are closely linked, but lactose intolerance results when a person exhibits symptoms related to poor digestion of lactose. Lactose intolerance also differs from a milk allergy, which occurs when your immune system cannot tolerate the protein in milk. Signs of lactose intolerance can include bloating, diarrhea, gas, nausea and stomach discomfort such as cramps or pain. They typically start a half-hour to two hours after you consume food with lactose. Although the symptoms of lactose intolerance tend to be mild, some people can experience more severe forms.
Milk Consumption
Some individuals with lactose intolerance can consume milk and dairy products if they control the portions and time of consumption to minimize symptoms. Strategies that help prevent or reduce gastrointestinal discomfort in many cases range from sipping milk slowly, to limiting servings to 4 oz. or less, to drinking milk only with other foods, such as during meals. Another option involves using nonprescription products containing lactase enzyme, such as drops you add to regular milk. The products help people with lactose intolerance digest the milk sugar by providing them with the required enzyme they lack.
Milk Alternatives
People with lactose intolerance who prefer to avoid regular milk can purchase reduced-lactose and lactose-free milk in many stores. The beverages contain added lactase to facilitate digestion of the milk sugar lactose. Stores also sell other beverages designed to replace regular milk, such as rice milk and soy milk. Although the milk substitutes do not have any problematic lactose, they often supply many of the nutrients found in milk, including calcium. Additional sources of calcium that the lactose intolerant can consume include fortified cereals, sardines, tofu, almonds, rhubarb and green vegetables like collards, spinach and broccoli.
References
- "Dietary Guidelines for Americans 2005"; U.S. Department of Health and Human Services, et al.; 2005
- Mayo Clinic; Lactose Intolerance; February 2010
- National Digestive Diseases Information Clearinghouse; Lactose Intolerance; June 2009
