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Lactose is the naturally occurring sugar in milk and milk products. Some people cannot break down and absorb the components of this sugar. It requires lactase, an enzyme found in the intestine, to break it down into smaller, more easily digested sugars. If this enzyme is lacking or the body does not produce enough, lactose cannot be fully broken down and ends up being fermented by the good bacteria in our intestinal tract. This results in symptoms such as nausea, cramping, bloating, abdominal pain, and gas. This condition is described as lactose intolerance.
Symptoms can occur 15 to 30 minutes to several hours after eating lactose-containing foods. The severity of symptoms will vary from person to person. Official diagnosis of lactose intolerance requires a lactose tolerance test, hydrogen breath test, or in children, stool acidity testing. More often than not, the diagnosis occurs based on symptoms and then elimination of dairy foods with reintroduction to see if symptoms return. It is important to note that lactose intolerance and a milk allergy are not the same. Lactose intolerance occurs because of the body's inability to digest the naturally occurring lactose, a milk carbohydrate. A milk allergy is the body's immune response to milk protein. People with a milk allergy must avoid all milk products to avoid a reaction, whereas a person with lactose intolerance can still consume milk and dairy products, though in limited amounts. Current research indicates that most individuals with lactose intolerance can still handle the amount of lactose found in one cup of milk (about 12 grams) with minor to no symptoms. Smaller amounts (less than 6 grams per serving) are unlikely to result in any symptoms. The table below lists common foods and the amount of lactose they contain.
Ways to Minimize Symptoms
The National Dairy Council offers these tips to help minimize symptoms:
- Try it: opt for lactose-free products, which provide the same nutrients as dairy foods but without lactose.
- Sip it: introduce dairy slowly; start with a ¼ cup of milk and gradually increase.
- Stir it: mix milk with food; don't consume milk and other dairy foods on their own; always combine with other foods.
- Slice/shred it: choose aged cheeses; add a slice to sandwiches or shred on veggies.
- Spoon it: try yogurt.
You may want to consider the following products on your next shopping trip:
- Try reduced lactose or lactose-free milk such as Lactaid®, or other lactose-free dairy products
- Look for yogurt, kefir, and buttermilk with "live and active" cultures, which help digest lactose.
- Choose cheeses that are naturally lower in lactose, like Swiss, Colby, Parmesan, and cheddar. They lose most of their lactose through processing and aging.
- Take lactase enzyme capsules or drops (e.g., Lactaid®, Dairy-Ease®) at the beginning of your meal to aid digestion of lactose-containing foods.
- Try plant-based milks, such as soy, almond, or rice, that are fortified with calcium and vitamin D
|1 cup yogurt (low fat)||11-17|
|1 cup milk (whole, 2%, 1%, fat free)0||11-13|
|½ cup cottage cheese (low fat, 2%)||2-3|
|1 ounce aged cheese (cheddar, Swiss, mozzarella)||0.3-1|
|1 cup Lactaid milk (low fat, lactose free)||0|
Tip: "Lactose intolerance is not an 'all or nothing' condition. Instead, it is a matter of degree. Learn to manage the amount of lactose you consume; know your own tolerance level!" --American Dietetic Association Complete Food and Nutrition Guide, 4th Edition
Tips Affecting Different Age Groups
As we age, our bodies gradually produce less lactase, resulting in some degree of lactose maldigestion or, when symptoms occur, lactose intolerance. African Americans, Hispanics, Asians, and Native Americans are more likely to be lactose intolerant. People of Jewish or Mediterranean background are also often intolerant. Milk and dairy foods are important sources of calcium, protein, riboflavin, vitamins A and D, magnesium, potassium and other nutrients essential for good health and bone health in particular. Therefore, it is important to realize that you should not give up these foods even with lactose intolerance. The key is to consume them to your tolerance level; it is really a matter of degree!
People are less able to digest lactose as they get older. They make less of the enzyme called lactase that breaks down the sugar. African American, Hispanic, Asian, and Native Americans are more likely to be lactose intolerant. People of Jewish or Mediterranean background are also often lactose intolerant. Use lactose-free, lactose-reduced, fortified milk substitute for any recipe that uses milk as an ingredient, or take lactase enzyme tablets when you eat dairy foods. Try the recipe below for pudding.
Reduced-Lactose Yogurt Pudding
Serving size: Makes 4 servings (1/2 cup each)
- 1 cup nonfat plain yogurt
- 1 cup lactose-free low-fat milk
- 1 small package instant vanilla pudding mix
Mix all ingredients together. Beat until smooth and thickened. Refrigerate until ready to serve. Serve with fresh or canned fruit.
80 calories, 0 g total fat, 1 mg cholesterol, 170 mg sodium, 14 g carbohydrates, 6 g protein, 188 mg calcium.
Examine Your Choices
|Food||Source||What I buy||What I plan to buy|
|Milk||Good source of calcium and vitamin D||Juice and iced tea||Lactose-free milk|
Reintroduce milk in my diet. Start with 1/4 cup with supper and gradually include a 1/4 cup at breakfast and lunch as well over the next 3 weeks. _____________________________________________________________________________
Duyff, R. American Dietetic Association Complete Food and Nutrition Guide. 4th ed. Hoboken, NJ: John Wiley and Sons, 2012.
Jarvis, J. "Flexibility Is Key when Managing Lactose Intolerance." DairyGood.org, February 23, 2016.
Savaino, D., and V. Meredith. Rethinking Lactose Intolerance: A Guide for Including Dairy Foods in the Diet. West Lafayette, IN: Purdue Extension, 2015.
Webb, D. "The Latest on Lactose Intolerance." Today's Dietitian 17, no. 5 (2015): 38-41.
Prepared by Lois Killcoyne, former Penn State extension educator. Revised by Sharon McDonald, extension educator.