LACTOSE INTOLERANCE

Lactose Intolerance

Jessie was so embarrassed! About an hour after chowing down on pizza and ice cream with a group of friends, her stomach suddenly started rumbling, and she began farting over and over. Then Jessie's stomach began to ache and she had to run to the restroom every few minutes. In the excitement of an afternoon hanging out at the mall, Jessie had forgotten to watch her dairy intake. Jessie has lactose intolerance and her symptoms flare up when she eats more dairy than her body can handle.

What Is Lactose Intolerance and What Causes It?
Lactose intolerance is the inability to digest a sugar called lactose that is present in milk and dairy products. Normally when you eat something containing lactose, the body produces an enzyme called lactase in the small intestine. Lactase breaks down lactose into simpler sugar forms called glucose and galactose, which are then easily absorbed into the bloodstream and turned into energy - fuel for our bodies.

People with lactose intolerance do not produce enough of the lactase enzyme to break down lactose. Instead undigested lactose sits in the gut causing gas, bloating, and stomach cramps, and then usually diarrhea because the intestine cannot absorb the lactose-containing foods.

The American Dietetic Association estimates that between 30 and 50 million Americans are lactose intolerant. Lactose intolerance seems to affect guys and girls equally. But certain ethnic groups are more likely to be affected. About 90% of Asian Americans are lactose intolerant, and up to 75% of African Americans, Hispanic Americans, and Native Americans also have symptoms of lactose intolerance.

Most people eventually become lactose intolerant in adulthood - some while they are still in their teen years. Many health care providers view lactose intolerance as a normal human condition likely to occur in the majority of people in the world (especially as they get older), and therefore don't really consider lactose intolerance a true disease.

Who Gets Lactose Intolerance?
There are different reasons why a person may be or may become lactose intolerant:

• People who are of Asian, African, Native American, and Hispanic backgrounds are more likely to develop lactose intolerance at a younger age.
• People with irritable bowel syndrome or Crohn's disease have a reduced level of the lactase enzyme.
• Certain antibiotics can trigger temporary lactose intolerance by interfering with the intestine's ability to produce the lactase enzyme.
• After a bout of infectious diarrhea, some kids can develop a temporary lactose intolerance that usually improves after a few days or weeks.
• As people get older, their bodies usually stop producing the lactase enzyme, and most people will naturally become lactose intolerant over time.

What Happens to People With Lacose Intolerance?
Depending on how much dairy or how many milk-containing foods you eat and how little lactase you produce, you could have a variety of symptoms.

Usually within 30 minutes to 2 hours after eating, someone with lactose intolerance will experience nausea, stomach cramps, bloating, gas, and diarrhea. This can be unpleasant and embarrassing if you're at school or out with friends.

Because many people may think they're lactose intolerant when they really aren't, it's important to watch what you eat to figure out if dairy products really are the problem. It can also help to see a doctor who can diagnose the condition correctly and advise you on steps you can take to manage it.

How Do Doctors Diagnose It?
The most common test for lactose intolerance is the hydrogen breath test. This is a simple test that can be performed by your doctor. Normally very little hydrogen gas is detectable in the breath. However, undigested lactose in the colon ferments (breaks down) and produces various gases, including hydrogen.

For the hydrogen breath test, your doctor will ask you to blow into a tube for a beginning sample. You'll then swallow a drink with lactose in it or eat lactose-containing food, wait 30 minutes, and breathe into the tube again. The hydrogen level of the sample is then checked.

Doctors can also find out if you are able to digest lactose by testing for the presence of lactase during a procedure called endoscopy. During this procedure, doctors view the inside of the intestines by inserting a long tube with a light and a tiny camera on the end into the mouth or rectum. They can then take tissue samples and pictures of the inside of your gut and look for clues as to why you've been having problems with what you're eating.

Living Wtih Lactose Intolerance
A person's body doesn't need lactose to be healthy. After early childhood, milk is a good source of nutrition but it's not absolutely necessary in the diet. (Calcium is very important, though, especially in teens, for good health and bone growth.)

Lactose intolerance is a very individual condition and it's often easy to manage if you're in tune with your body. Most people with lactose intolerance are able to eat a small amount of dairy, but the trick is to remember to always eat the dairy in combination with other foods that don't contain lactose and not go overboard. But because each case is different, there's no one simple way of dealing with it. Each person needs to learn the strategies that work best for him or her depending upon the symptoms and how much, if any, lactase the body produces.

Teens with the most severe symptoms of lactose intolerance must avoid all dairy products. Others can control problems by keeping a food diary and learning what they can and can't tolerate.

Because growing teens need about 1,200 milligrams (mg) of calcium each day, it's extremely important that teens who have to eliminate dairy products from their diets find other good calcium sources. It's probably a good idea to seek help from a registered dietitian. Dietitians are trained in nutrition and they can help people who are lactose intolerant come up with eating alternatives and develop a well-balanced diet that provides lots of calcium for developing strong bones.

Here are some other tips for dealing with lactose intolerance:

• Choose lactose-reduced or lactose-free milk.
• Take a lactase enzyme supplement (such as Lactaid) just before you eat dairy products. These can be taken in drops or tablets and even added directly to milk (they tend to make milk taste a bit sweeter if left for a long time).
• When you do drink milk or eat lactose-containing foods, eat other non-lactose foods at the same meal to slow digestion and avoid problems. (For example, if you are going to have a milkshake, don't drink it by itself. Have something else with it - like a healthy sandwich.)
• Drink juices that are fortified with calcium.
• Eat a variety of dairy-free foods that are rich in calcium, such as leafy greens (like spinach, brussels sprouts, or broccoli).
• Consider hard (aged) cheeses such as cheddar, which are lower in lactose.
• Try tofu or soy milk. These foods are high in calcium and can be prepared in dozens of different ways.
• Yogurts that contain active cultures are easier to digest and much less likely to cause lactose problems.
• Eliminating dairy can also reduce a person's intake of vitamin D. But several minutes in the sun two or three times a week should allow your body to produce enough vitamin D on its own.
• Learn to read food labels. Lactose is added to some boxed, canned, frozen, and prepared foods like bread, cereal, lunch meats, salad dressings, mixes for cakes and cookies, and coffee creamers. Be aware of certain words that may mean the food has lactose in it: butter, cheese, cream, dried milk, milk solids, powdered milk, and whey, for example.

Reviewed by: John Tung, MD
Date reviewed: June 2004