What is lactose intolerance?
Lactose intolerance is the inability to digest lactose, the sugar primarily found in milk and dairy products. It is caused by a shortage of lactase in the body, an enzyme produced by the small intestine that is needed to digest lactose. While lactose intolerance is not dangerous, its symptoms can be distressing.
Who is affected by lactose intolerance?
For most people, lactose intolerance develops over time as the body produces less lactase.
It is estimated that 30 to 50 million Americans have some degree of lactose intolerance. Lactose intolerance affects people from certain ethnic populations and races—such as Latin Americans, African-Americans, Native Americans, Asians, East Europeans and Middle Easterners—more than others.
How do I know if processed foods contain lactose?
When buying food, read the ingredients on food labels carefully. Ingredients derived from milk that contain lactose include:
- Milk by-products
- Dry milk solids
- Nonfat dry milk
- Dry milk powder
Also avoid items that state "may contain milk" on the food label. Depending on the severity of your symptoms, you may need to avoid or limit foods containing these ingredients.
Lactose is also present in about 20 percent of prescription medications, such as birth control pills (oral contraceptives), and about six percent of over-the-counter medications, such as some tablets for stomach acid and gas. Viactiv® calcium chews contain lactose and should be avoided while following a lactose-free diet.
These medications usually affect only people with severe lactose intolerance. Ask your healthcare provider which medications contain lactose, and read the labels on over-the-counter medications to check their lactose content.
What foods are high in lactose?
The most common high-lactose foods include:
- Milk, milkshakes and other milk-based beverages
- Whipping cream and coffee creamer
- Ice cream, ice milk, sherbet
- Puddings, custards
- Cream soups, cream sauces
- Foods made with milk
Other foods that MAY contain lactose in smaller quantities include:
- Bread and baked goods
- Milk chocolate
- Salad dressings and sauces
- Breakfast cereals and cereal bars
- Instant potatoes, soups, rice and noodle mixes
- Candies and other snacks
- Mixes for pancakes, biscuits, and cookies
- Organ meats (such as liver)
- Sugar beets, peas, lima beans
What causes lactose intolerance?
Lactose intolerance is caused by a shortage of lactase in the body, an enzyme produced by the small intestine that is needed to digest lactose. Some causes of lactose intolerance are known. Certain digestive diseases, such as Crohn's disease, ulcerative colitis, celiac sprue (an inherited disorder affecting the lining of the small intestine), other inflammatory bowel diseases, and injuries to the small intestine (surgery or trauma) may reduce the amount of lactase available to process lactose properly. If the small intestine is injured, lactose intolerance may be temporary, with symptoms improving after the intestine has healed.
What are the symptoms of lactose intolerance?
Symptoms of lactose intolerance include nausea, cramps, gas, bloating, or diarrhea within 30 minutes to 2 hours after consuming milk or dairy products. Symptoms occur because there is not enough lactase being produced by the body to digest the lactose consumed. The severity of symptoms varies, depending on the amount of lactose an individual person can tolerate. Some people may be sensitive to extremely small amounts of lactose-containing foods while others can eat larger amounts before they notice symptoms. Age and digestion rate may influence how much lactose an individual may tolerate.