There are two main ways to treat lactose intolerance:
Reduce the amount of lactose you eat, by limiting milk and dairy products
Taking commercially available enzyme substitutes
People with lactose intolerance need to read labels of all prepared foods to see if they contain lactose. The highest concentrations are found in ice cream and milk. Cheeses typically have lower amounts of lactose. Some products listed as nondairy, such as powdered coffee creamer and whipped toppings, may contain lactose if they contain ingredients that are derived from milk. When you read food labels, look for words such as whey, curds, milk byproducts, dry milk solids and nonfat dry milk powder. If any of these ingredients are on the label, the product probably contains lactose.
If you completely avoid lactose, your symptoms should go away. If they do not, the diagnosis might not be correct. Many people will be able to tolerate a gradual increase in lactose intake if they are careful to monitor their symptoms. Doctors often recommend ice cream for this. It tends to be tolerated better than other foods that contain lactose because of its high fat content. As you gradually increase your lactose levels, review your diet with your doctor or a nutritionist to be sure that you are eating the proper proportions of fat, protein and other nutrients.
There are several commercially available enzyme formulations (tablets and liquids) that can serve as lactase replacements. You can add these to foods that contain lactose to reduce symptoms significantly. However, these products rarely get rid of symptoms completely, and the results vary among people and with different product formulations. Pretreated dairy products are an extremely effective alternative. You can add enzyme drops to milk and then refrigerate the milk for 24 hours before use or you can purchase dairy products that have been treated to reduce the lactose ("lactose-free" milk). "Acidophilus" milk still has too much lactose to be useful for most people with lactose intolerance.
Many people with lactose intolerance have a difficult time getting enough calcium in their diet. Also they may have low levels of vitamin D. This increases the risk of osteoporosis, a condition in which bones become thin and fragile. Therefore, be sure to consume at least 1,000 milligrams of calcium each day (1,200 milligrams if you are a postmenopausal woman) and get at least 600 International Units of vitamin D daily. Most people with lactose intolerance are able to tolerate live culture yogurt, one good source of calcium. Vegetables such as broccoli, Chinese cabbage, collard greens and kale are also excellent sources of calcium. If you are not able to get enough calcium in your diet, you may need a daily calcium supplement.