Lactose intolerance: Your guide to prevention

What is lactose intolerance?

Lactose intolerance is your body’s inability to digest foods with lactose in them. Lactose is the sugar found in milk and foods made with milk (ice cream, cheese). Sometimes, this condition is called dairy product intolerance, lactase deficiency or milk intolerance. Lactose intolerance typically causes discomfort in your stomach. For example, After eating foods with lactose in them, you may feel sick to your stomach. It is a common problem. Babies have the lactase enzyme, so they are not lactose intolerant (although premature babies may not have the enzyme). Lactose intolerance may first appear in children at the age of 3.

There are three types of lactose intolerance:

• Primary lactose intolerance: This represents people who used to drink milk as infants. But as they reduced their milk consumption, their guts slowed their lactase production. By the time they become adults, they find it difficult to digest milk and other dairy products.
• Secondary lactose intolerance: This represents people who experience an injury or illness to their gut, which changes their production of lactase considerably. Such illnesses include Crohn’s disease and celiac disease.
• Congenital lactose intolerance: This represents people who have a genetic reason for having the condition. It is rare and both parents must have this gene to pass it onto their children.

Understanding lactose intolerance: Key facts and causes

• Lactose intolerance often develops in adulthood as lactase production naturally decreases, although it can also occur in children and infants.
• Lactose intolerance is not a milk allergy.
• It’s not life-threatening.
• Lactose intolerance is more common in certain ethnic groups, including individuals of African, Asian, Hispanic, and Native American descent.

Symptoms of lactose intolerance

Symptoms include:

• Nausea
• Stomach cramps/pain
• Bloating
• Gas
• Diarrhea
• Gurgling in your stomach

The amount of lactose an individual can tolerate varies. Some can consume small amounts without symptoms, while others need to completely avoid dairy.

What causes lactose intolerance?

Lactose intolerance is caused by the missing enzyme, lactase. Lactase lives in your small intestine. Some people don’t have it because of infection, celiac disease, Crohn’s disease, or ulcerative colitis. In rare cases, it is genetic.

How to identify and avoid lactose intolerance

Most people suspect they are lactose intolerant when they experience stomach upset after digesting foods containing dairy. If you believe you are lactose intolerant, here’s how to reduce your risk for stomach upset:

• Avoid eating or touching any foods with dairy. Sometimes dairy is an ingredient you wouldn’t suspect to be in a certain meal or snack. If you are at a restaurant, you’re your server about the ingredients in the food you order. Sometimes you can still order the dish without dairy (skip the cheese, for example). Be sure to tell your server you cannot have dairy.
• Read the ingredients and all other important warnings on labels of packaged goods. Even if a product doesn’t contain dairy, it may have been manufactured in a facility that is exposed to it. Some products come with a warning that it was made near other products containing dairy.
• Tell all your health care providers you are lactose intolerant.

Carry the medicine you need to manage your lactose intolerance. Some medicines can be taken in advance of consuming dairy to minimize discomfort. Some medicines are designed to provide relief if you chose to or accidentally consumed dairy.

How is lactose intolerance diagnosed and tested?

A doctor can diagnose lactose intolerance through one or multiple tests.

• The milk challenge: This is the easiest way to diagnose lactose intolerance. Avoid eating and drinking all dairy products for several days. This includes milk, ice cream, and cheese. Drink a glass of milk. If you have stomach problems an hour later, you are probably lactose intolerant. If you aren’t sure, see your doctor. Your doctor will ask you questions about your symptoms and your history with dairy products.
• A blood or saliva test: This allows your doctor to test for lactose intolerance or the gene. You will be asked to drink a beverage with lactose in it. Two hours later, your doctor will draw your blood or collect a saliva sample to send to a lab.
• A hydrogen breath test. This can be done in a hospital, lab, or your doctor’s office. You will be asked to drink a beverage that contains lactose. After 15 minutes, you’ll be asked to blow into balloon-like bags every 15 minutes. The air inside the bags will be tested for hydrogen. If your air contains a lot of hydrogen, you are probably lactose intolerant. The full test takes about 2 hours.
• Stool acidity test (where you provide a stool sample). This is a common test for infants and young children.
• Genetics test. This involves taking a sample of your genes through a blood or a saliva (spit) sample.
• A surgical biopsy of your intestine. This is done at a hospital. It requires anesthesia (medicine that puts you into a deep sleep). Your doctor will make a small cut in your stomach near your small intestine. He or she will take a sample. It will be sent to a lab.

Preventing lactose intolerance: Steps to stay safe

You can reduce stomach discomfort and other symptoms of lactose intolerance by doing the following:

• Cut back on the amount of dairy you eat or drink. One serving of milk should be ¼ or ½ cup.
• Have food in your stomach (not more dairy).
• Wait several hours before having more dairy.
• Choose foods with less lactose. Those include buttermilk and hard cheeses (cheddar, parmesan, Romano), ice cream, and goat cheese.
• Substitute soy or nondairy products. Use a nondairy coffee creamer.
• Take supplements that help you digest lactose (Lactaid). These are pills you can chew before you eat or drink dairy.
• Look for lactose-free foods in the grocery store.
• Eat yogurt (if you can). Yogurt helps with stomach upset. Many different probiotics can lessen the symptoms of lactose intolerance, so these could be a good supplement if you do not tolerate yogurt.
• Talk to your doctor about vitamin supplements. Eat foods that are naturally high in calcium. These include leafy greens, oysters, sardines, canned salmon, shrimp, and broccoli.
• Choose orange juice and cereals with added calcium.
• Eliminate the possibility of cross-contamination in food preparation areas by asking your host, restaurant server, and reading package labels.

Emergency preparedness: Handling lactose intolerance

Lactose intolerance doesn’t have a cure, but symptoms can be managed through dietary changes, such as avoiding high-lactose foods or using lactase enzyme supplements. Watch what you eat and drink to reduce stomach pain, gas, and diarrhea.

Practical tips for managing lactose intolerance

Living with stomach pain, gas, and bloating is uncomfortable. Monitor what you eat and drink. Limit your dairy to make you feel more comfortable. Lactose intolerance can potentially lead to nutrient deficiencies if it prevents individuals from getting enough calcium and vitamin D from dairy sources. Ask your doctor for the best methods of improving your calcium and vitamin D consumption.

Consider these milk substitutes, which may be easier to digest:

• Buttermilk and cheeses, including aged hard cheeses (these foods contain less lactose than milk)
• Fermented milk products, such as yogurt
• Goat’s milk
• Lactose-free milk and milk products
• Lactase-treated cow’s milk for older children and adults
• Soy formulas for infants younger than 2 years
• Soy or rice milk for toddlers

Questions to ask your doctor

• How should I handle avoiding lactose intolerance?
• Are the symptoms usually the same and same intensity?
• Is lactose intolerance inherited?
• Do symptoms appear in a certain order to give you some warning?
• Can you develop lactose intolerance later in life?
• Could gas, bloating, diarrhea, and pain be a sign of something else?
• Can you build up a tolerance for lactose as you age?
• Do I need to take a calcium supplement if I don’t have dairy in my diet?