Lactose is a sugar found in dairy products. Many people have a low level of lactase, the protein enzyme needed to digest lactose. If the amount of lactase in the body falls below a certain level, clinical symptoms of lactose intolerance may result. Typical symptoms of lactose intolerance include:

  • Diarrhea
  • Bloating and flatulence
  • Abdominal pain

The tendency to have decreased levels of lactase varies by country, race and ethnic group. In the United States, it is estimated that 60% to 90% of adult Blacks and Orientals have lactose malabsorption compared with 5% to 15% of adult Whites of northern European extraction.


Even if you have reduced amounts of lactase in your digestive system, you may still be able to tolerate some dairy products. For example, many people can tolerate yogurt if it contains active bacterial cultures. Many frozen yogurts do not contain these cultures at all or contain insufficient quantities of them.


If you eat or drink dairy products, it may be more helpful to do so in small quantities at different times throughout the day. Also, some dairy products may be easier to tolerate than others. For example, some people may tolerate whole milk but not skim milk. This is because the fats in whole milk may slow the passage of milk through the digestive tract and improve your digestion of lactose. It may also help to consume milk products with solid foods to slow the rate of passage through your digestive system.

Low-lactose milk may also relieve milk intolerance. On the other hand - and contrary to prior expectations - certain milk forms do not appear to alleviate symptom response (such as sweet acidophilus milk).


Foods That Contain Lactose


Dairy Products

Milk, low-fat milk, skim milk, chocolate milk, buttermilk (all contain similar amounts; some people may digest fatted or sweetened milk better than skim milk)
Sweetened condensed milk (contains more lactose than regular milk)
Dried whole milk, instant nonfat dry milk (contains less lactose than regular milk)
Low-fat yogurts (contain about as much lactose as milk, but unpasteurized yogurts with active bacterial cultures are often easier to digest)
Frozen yogurts (often lack active bacterial cultures or contain insufficient amounts)
Ice cream
Ice milk
Cheese (most common types contain similar amounts of lactose)
Cottage cheese (contains about half as much lactose as milk)
Cream (whipped topping, light, half and half)


Other Foods That May Contain "Hidden" Lactose

"Non-dairy" creamers
Powdered artificial sweeteners
Foods containing milk powder or nonfat milk solids

Margarine (including some labeled as 100% corn oil)
Creamed soups
Pancakes, waffles
Puddings, custards

Confections (including chocolate)
Certain meat products


Revised 8/08 



ŠTed A. Tobey, M.D., Inc. ~ All Rights Reserved