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The information contained in this section has been procured from  the Mayo Clinic and John Hopkins Medicine.

It is all for educational purposes and not intended to be taken as medical advice.

What is Lactose Intolerance?

Lactose intolerance is when your body can't break down or digest lactose. Lactose is a sugar found in milk and milk products.

Lactose intolerance happens when your small intestine does not make enough of a digestive enzyme called lactase. Lactase breaks down the lactose in food so your body can absorb it. People who are lactose intolerant have unpleasant symptoms after eating or drinking milk or milk products. These symptoms include bloating, diarrhea, and gas.

Lactose intolerance is not the same thing as having a food allergy to milk.

Lactose intolerance is most common in Asian Americans, African Americans, Mexican Americans, and Native Americans.

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Source: John Hopkins Medicine

Lactose Intolerance

What causes Lactose Intolerance?

Lactose intolerance occurs when your small intestine doesn't produce enough of an enzyme (lactase) to digest milk sugar (lactose).

Normally, lactase turns milk sugar into two simple sugars — glucose and galactose — which are absorbed into the bloodstream through the intestinal lining.

If you're lactase deficient, lactose in your food moves into the colon instead of being processed and absorbed. In the colon, normal bacteria interact with undigested lactose, causing the signs and symptoms of lactose intolerance.

Source: Mayo Clinic

Types of Lactose Intolerance

There are three types of lactose intolerance. Different factors cause the lactase deficiency underlying each type.

1. Primary lactose intolerance

People who develop primary lactose intolerance — the most common type — start life producing enough lactase. Infants, who get all their nutrition from milk, need lactase.

As children replace milk with other foods, the amount of lactase they produce normally drops, but usually remains high enough to digest the amount of dairy in a typical adult diet. In primary lactose intolerance, lactase production falls off sharply by adulthood, making milk products difficult to digest.

2. Secondary lactose intolerance

This form of lactose intolerance occurs when your small intestine decreases lactase production after an illness, injury or surgery involving your small intestine. Diseases associated with secondary lactose intolerance include intestinal infection, celiac disease, bacterial overgrowth and Crohn's disease.

Treatment of the underlying disorder might restore lactase levels and improve signs and symptoms, though it can take time.

3. Congenital or developmental lactose intolerance

It's possible, but rare, for babies to be born with lactose intolerance caused by a lack of lactase. This disorder is passed from generation to generation in a pattern of inheritance called autosomal recessive, meaning that both the mother and the father must pass on the same gene variant for a child to be affected. Premature infants can also have lactose intolerance because of an insufficient lactase level.

SourceMayo Clinic


Who is at risk for Lactose Intolerance?

Factors that can make you or your child more prone to lactose intolerance include:

  • Increasing age.  Lactose intolerance usually appears in adulthood. The condition is uncommon in babies and young children.

  • Ethnicity.  Lactose intolerance is most common in people of African, Asian, Hispanic and American Indian descent.

  • Premature birth.  Infants born prematurely might have reduced levels of lactase because the small intestine doesn't develop lactase-producing cells until late in the third trimester.

  • Diseases affecting the small intestine.  Small intestine problems that can cause lactose intolerance include bacterial overgrowth, celiac disease and Crohn's disease.

  • Certain cancer treatments.  If you've had radiation therapy for cancer in your stomach or you have intestinal complications from chemotherapy, your risk of developing lactose intolerance increases.


SourceMayo Clinic

What are the symptoms of Lactose Intolerance?

Each person’s symptoms may vary.  Symptoms often start about 30 minutes to 2 hours after you have food or drinks that have lactose.

Symptoms may include:

  • Belly (abdominal) cramps and pain

  • Bloating

  • Gas

  • Diarrhea

  • Nausea, and sometimes, vomiting


How severe your symptoms are will depend on how much lactose you have had. It will also depend on how much lactase your body makes.

The symptoms of lactose intolerance may look like other health problems. Always see your healthcare provider to be sure.


Source: John Hopkins Medicine

SourceMayo Clinic


How is Lactose Intolerance diagnosed and tested for?

Your doctor might suspect lactose intolerance based on your symptoms and your response to reducing the amount of dairy foods in your diet. Your doctor can confirm the diagnosis by conducting one or more of the following tests:

  • Hydrogen breath test.  After you drink a liquid that contains high levels of lactose, your doctor measures the amount of hydrogen in your breath at regular intervals. Breathing out too much hydrogen indicates that you aren't fully digesting and absorbing lactose.

  • Lactose tolerance test.  Two hours after drinking a liquid that contains high levels of lactose, you'll undergo blood tests to measure the amount of glucose in your bloodstream. If your glucose level doesn't rise, it means your body isn't properly digesting and absorbing the lactose-filled drink.

  • Stool acidity test.  This test is used for infants and young children. It checks how much acid is in the stool. If someone is not digesting lactose, their stool will have lactic acid, glucose, and other fatty acids.  

Source: John Hopkins Medicine

SourceMayo Clinic


How is Lactose Intolerance treated?

There is no treatment that can help your body make more lactase. But you can manage your symptoms by changing your diet.

In the past, people who were lactose intolerant were told to stop taking dairy products. Today, health experts suggest you try different dairy foods and see which ones cause fewer symptoms. That way you can still get enough calcium and other important nutrients.

Lactose intolerance symptoms can be unpleasant, but they won’t hurt you. So try to find dairy foods that don’t cause severe symptoms.

Here are some tips for managing lactose in your diet:

  • Start slowly.  Try adding small amounts of milk or milk products and see how your body reacts.

  • Have milk and milk products with other foods.  You may find you have fewer symptoms if you take milk or milk products with your meals.  Try eating cheese with crackers or having milk with cereal.   

  • Eat dairy products with naturally lower levels of lactose.  These include hard cheeses and yogurt.

  • Look for lactose-free and lactose-reduced milk and milk products.  These can be found at many food stores. They are the same as regular milk and milk products. But they have the lactase enzyme added to them.

  • Ask about lactase products.  Ask your healthcare provider if you should take a lactase pill or lactase drops when you eat or drink milk products.

Children with lactose intolerance should be seen by a healthcare provider. Children and teenagers need dairy foods. They are a major source of calcium for bone growth and health. They also have other nutrients that children need for growth.


Source: John Hopkins Medicine

Living with Lactose Intolerance

With some trial and error,  you might be able to predict your body's response to foods containing lactose and figure out how much you can eat or drink without discomfort.


Few people have such severe lactose intolerance that they have to cut out all milk products and be wary of nondairy foods or medications that contain lactose.

It’s important to read food labels. Lactose is often added to some boxed, canned, frozen, and prepared foods such as:

  • Bread

  • Cereal

  • Lunch meats

  • Salad dressings

  • Cake and cookie mixes

  • Coffee creamers


Check food labels for words that may mean a food has lactose in it, such as:

  • Butter

  • Cheese

  • Cream

  • Dried milk

  • Milk solids

  • Powdered milk

  • Whey

Source: John Hopkins Medicine

Maintaining a Good Dietary Plan

Reducing the dairy products doesn't mean you can't get enough calcium. Calcium is found in many other foods, such as:

  • Broccoli and leafy green vegetables

  • Calcium-fortified products, such as cereals and juices

  • Canned salmon or sardines

  • Milk substitutes, such as soy milk and rice milk

  • Oranges

  • Almonds, Brazil nuts and dried beans


Also make sure you get enough vitamin D, which is typically supplied in fortified milk. Eggs, liver and yogurt also contain vitamin D, and your body makes vitamin D when you spend time in the sun.

Even without restricting dairy foods, though, many adults don't get enough vitamin D. Talk to your doctor about taking vitamin D and calcium supplements to be sure.

Source: Mayo Clinic


Limit Dairy Products

Most people with lactose intolerance can enjoy some milk products without symptoms. You might tolerate low-fat milk products, such as skim milk, better than whole-milk products. It also might be possible to increase your tolerance to dairy products by gradually introducing them into your diet.

Ways to change your diet to minimize symptoms of lactose intolerance include:

  • Choosing smaller servings of dairy.  Sip small servings of milk — up to 4 ounces (118 milliliters) at a time. The smaller the serving, the less likely it is to cause gastrointestinal problems.

  • Saving milk for mealtimes.  Drink milk with other foods. This slows the digestive process and may lessen symptoms of lactose intolerance.

  • Experimenting with an assortment of dairy products.  Not all dairy products have the same amount of lactose. For example, hard cheeses, such as Swiss or cheddar, have small amounts of lactose and generally cause no symptoms.

    Ice cream and milk contain the most lactose, but the high fat content in ice cream might allow you to eat it without symptoms. You might tolerate cultured milk products such as yogurt because the bacteria used in the culturing process naturally produce the enzyme that breaks down lactose.

  • Buying lactose-reduced or lactose-free products.  You can find these products at most supermarkets in the dairy section.

  • Using lactase enzyme tablets or drops.  Over-the-counter tablets or drops containing the lactase enzyme (Lactaid, others) might help you digest dairy products. You can take tablets just before a meal or snack. Or the drops can be added to a carton of milk. These products don't help everyone who has lactose intolerance.

Source: Mayo Clinic


Alternative Medicine


Probiotics are living organisms present in your intestines that help maintain a healthy digestive system. Probiotics are also available as active or "live" cultures in some yogurts and as supplements in capsule form.  


They are sometimes used for gastrointestinal conditions, such as diarrhea and irritable bowel syndrome.   


They might also help your body digest lactose. Probiotics are generally considered safe and might be worth a try if other methods don't help.

Source: Mayo Clinic

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