What is lactose?

Milk and milk products contain a sugar called lactose. Some people cannot tolerate high amounts of lactose and can develop lactose intolerance. It’s important to understand how much lactose your body can tolerate.
Lactose is a natural sugar that is present in milk. It is a source of energy. It also helps babies grow and develop.
When you drink milk or eat dairy products, lactose enters your digestive system and goes to the small intestine. Your small intestine makes a digestive enzyme called lactase to break down lactose and absorb it into your body.
Research has shown that lactose may help your body absorb minerals like calcium and magnesium. It may also promote the growth of good bacteria in your gut.
Lactose in dairy products
Typically, about 8.5 ounces of cow’s milk and goat’s milk contain 12.92 grams and 11.47 grams of lactose, respectively.
Ripened cheeses have low levels of lactose as bacteria ferment lactose into lactic acid.
On average, 3.5 ounces of milk products have the following amounts of lactose:
- Yogurt: 4 grams
- Cream: 3.5 grams
- Butter: 0.8 grams
- Cream cheese: 3.2 grams
- Cheddar cheese: 0.24 grams
- Parmesan: 0.16 grams
- Mozzarella: 0.08 grams
What is lactose intolerance?
The enzyme lactase usually helps babies break down their mother’s milk. Lactase production in your gut decreases as you age.
When your body makes less lactase, your gut can’t absorb the lactose you consume. You may have digestive problems like indigestion, bloating, diarrhea, and stomach aches. This is known as lactose intolerance.
Lactose intolerance is not as common in the U.S. and Europe as it is in other countries. An estimated 12% of Americans are estimated to have lactose intolerance, despite previous research that said the rate was much higher. It is more common in people from Asia, the Middle East, Africa, and a few Mediterranean countries.
Lactose intolerance can happen due to underlying diseases including:
- Celiac disease, when you have inflammation in your small intestine that flares up when exposed to gluten.
- Gastroenteritis, when your stomach and intestines are inflamed.
- Crohn’s disease, a chronic inflammatory disease that affects your gastrointestinal (GI) tract.
- Cystic fibrosis, a genetic disease that affects organs including your intestines, lungs, pancreas, liver, and reproductive organs.
- Cancer
Lactose intolerance can also be genetic and pass on to you from your family.
Symptoms of lactose intolerance
Symptoms of lactose intolerance include:
- Stomach cramps and pain
- Bloating
- Farting
- Diarrhea
Talk to your doctor if you have these symptoms.

QUESTION
Pancreatitis is inflammation of an organ in the abdomen called the pancreas. See AnswerHow much lactose can you tolerate?
People with lactose intolerance can typically tolerate up to 12 grams of lactose. This is equal to one large cup or about 8 ounces of milk. Some can even have up to 12.5 ounces of milk without experiencing any symptoms.
You can test your tolerance for lactose by gradually adding more milk or other milk products to your diet. You may not have symptoms with one cup of milk, but you may have symptoms with a little more than one cup. You’ll know how much lactose you can tolerate and the exact portion you can have without any symptoms.
If you have symptoms, try having small amounts of milk and fermented milk products like yogurt or ripened cheese. This may help you keep lactose intolerance symptoms at bay.
Research has shown that having small amounts of lactose at regular intervals can reduce the unpleasant symptoms of lactose intolerance. You can try to have small portions of milk or dairy products at different times spread across the day. This allows your gut to easily digest the lactose without any discomfort.
It is also better to have milk after or while eating rather than to have it on an empty stomach. If you have lactose intolerance, you can have milk with cereals or add it to foods like mashed potatoes.
Your doctor may recommend that you have some dairy products to keep up your calcium levels. If your symptoms are severe, they may ask you to switch to plant-based alternatives like soy or almond milk.
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Diagnosing lactose intolerance
If you feel you have lactose intolerance, your doctor may perform the following tests to confirm your condition, though the diagnosis is usually made by listening to your symptoms and changing your diet:
- Elimination diet, where you stop eating foods with lactose for some time to see if your symptoms go away
- Hydrogen breath test, which shows undigested lactose
- Lactose tolerance test to check your blood sugar levels
- Stool acidity test to check for lactic acid in your stools
Treating lactose intolerance
Lactose intolerance can’t be cured. You’ll have to limit or eliminate foods or drinks containing lactose, like dairy products, to stop the symptoms. Your doctor may even prescribe calcium, vitamin D, and lactase supplements.
You can include the following in your diet:
- Lactose-reduced or lactose-free milk
- Plant-based milk like soy, oat, almond, and coconut milk
- Plant-based milk products like tofu
Foods to avoid
Apart from milk and milk products, the following foods can be hidden sources of lactose:
- Bread
- Biscuits and cakes with milk or milk solids
- Processed breakfast cereals
- Cheese sauce
- Cream soups
- Desserts with cream and milk
- Milk chocolate
- Pancakes
- Packaged foods with milk solids
- Margarine
- Salad dressings
- Candies
- Some medications
If you’re trying to avoid lactose, check the label before you buy packaged foods.

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BetterHealth Channel: "Lactose intolerance."
European Dairy Association (eda): "Lactose intolerance."
GI Society: "Lactose Intolerance."
Mayo Clinic: "Celiac disease," "Crohn's disease," "Cystic fibrosis," "Gastroenteritis: First aid."
NHS: "Overview: Lactose intolerance."
The University of Alabama at Birmingham: Nutrition Trends: "Lactose Intolerance May Not Be As Common As We Thought."
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The most common food allergies are to eggs, nuts, milk, peanuts, fish, shellfish, strawberries and tomatoes. Symptoms and signs of a food allergy reaction include nausea, vomiting, diarrhea, abdominal pain, itching, hives, eczema, asthma, lightheadedness, and anaphylaxis. Allergy skin tests, RAST, and ELISA tests may be used to diagnose a food allergy. Though dietary avoidance may be sufficient treatment for mild allergies, the use of an Epipen may be necessary for severe food allergies.How Do I Know if I Am Lactose Intolerant or Allergic to Milk?
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- Gas
- Abdominal pain
- Abdominal bloating
- Abdominal distention (swelling)
- Nausea
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