Lactose intolerance is caused by a reduction in the digestive enzyme lactase. Lactase breaks down the sugar lactose into sugars that can be more easily absorbed. When not fully broken down, lactose ferments in the colon and causes symptoms.
Some people are born unable to make lactase. Others develop the intolerance over time.
Symptoms of lactose intolerance generally begin within 2 hours of consuming milk or other dairy products. The severity of symptoms depends on how much lactase your body produces and how much lactose you eat.
Temporary lactose intolerance following an infection usually goes away after the intestine heals.
Treatment for chronic lactose intolerance focuses on managing symptoms. For most people, removing dietary lactose, especially in children and adolescents, would not be recommended. Milk and milk products provide sources of
and other food elements that are hard to replace. If complete elimination is chosen, then careful replacement of calcium is needed for good health.
Keep a food diary of what you eat and what the reaction is. Discuss the findings with your doctor or a dietitian.
Dietary changes may include:
Eat smaller amounts of milk or milk products with a meal. It may reduce symptoms. Many people can tolerate 4-8 ounces of milk. You may have better tolerance for some of the following dairy products made from milk:
Hard cheeses, such as cheddar and Swiss
Try lactose-free milk and lactose-reduced milk and milk products.
Ask a dietitian for help choosing substitutes for dairy products or recommending supplements to ensure that you eat enough calcium.
Nondairy foods rich in calcium include:
Read product labels because other foods can contain lactose including:
Instant potatoes, soups, and breakfast drinks
Liquid and powder milk-based meal replacements
Protein powders and bars
Non-dairy coffee creamers and whipped toppings
Other words that indicate lactose are:
Dry milk solids
Nonfat dry milk
Be aware that some medications may contain small amounts of lactose.
Your doctor may recommend lactase enzymes if you can tolerate only small quantities of lactose. The enzyme supplements come in liquid and chewable form. A few drops of the liquid added to milk, which is allowed to sit overnight, can decrease the amount of lactose in the milk. Tablets are chewed or swallowed before eating foods that contain lactose.
Heyman MB. Lactose intolerance in infants, children, and adolescents.
Lactose intolerance. National Institute of Diabetes and Digestive and Kidney Diseases website. Available at:
Updated June 2014. Accessed October 3, 2017.