backup og meta

Lactose Intolerance: Causes, Symptoms, Treatment

Medically reviewed by Mia Dacumos, MD · Nephrology · Makati Medical Center

Written by Nikita Bhalla · Updated Aug 19, 2022

Lactose Intolerance: Causes, Symptoms, Treatment

Lactose intolerance refers to the inability to digest lactose, a type of sugar in milk and other dairy products. After these dairy products are consumed, lactose reaches the small intestine, wherein it is broken down by lactase into simple forms of sugar like glucose and galactose.

Lactase is an enzyme produced by cells lining the small intestine. The simple forms of sugars make their way to the bloodstream and convert into energy for the human body. Lactose intolerance is usually considered to be a human condition and not a disease. 

This disorder can develop amongst children and adults across genders. In children, it occurs when they are unable to digest breast milk or formula. This leads to severe diarrhea, loss of weight, and dehydration. Lactose intolerance amongst children is also known as congenital lactase deficiency and congenital alactasia.

Symptoms of Lactose Intolerance

Below are the most common symptoms of the health condition. 

  • Flatulence
  • Bloating
  • Stomach cramps
  • Diarrhea
  • Nausea
  • Abdominal pain

When you experience any of the above symptoms within 30 minutes to 2 hours of consuming any dairy product, seek the advice of a doctor.

Causes of Lactose Intolerance

Individuals with lactose intolerance are unable to produce sufficient quantities of the lactase enzyme, a condition referred to as lactase non-persistence. Hence, they find it difficult to break down milk and other dairy products. The undigested lactose remains in the gut until bacteria break it down. This causes bloating, flatulence, stomach cramps, and diarrhea between 30 minutes to 2 hours of consuming dairy products.

Some people with lactose intolerance can digest restricted quantities of dairy products. While some others are averse to fresh milk but can digest other dairy products that are comparatively easier to digest like yogurt and cheese. This is because milk products like yogurt and cheese undergo a fermentation process in which most of the lactose content gets broken down.

Risk Factors of Lactose Intolerance

Below are the common risk factors of the health condition. 

  • Age. Increasing age may reduce or stop the production of lactase, making elderly people lactose intolerant over time. 
  • Medicines. Intake of certain medicines may lead to lactase non-persistence. These medicines affect the production of the lactase enzyme. 
  • Infection. Diarrheal infection amongst children may cause lactose intolerance for a few days or weeks.
  • Other digestive disorders. People with upper small intestinal disorders like Crohn disease or celiac disease produce lower amounts of lactase enzyme.
  • Ethnic background. Young people with Asian, Native American, African, and Hispanic backgrounds are at a higher risk of being lactose intolerant.

lactose intolerance

Diagnosis of Lactose Intolerance

Below is the diagnostic procedure usually followed for the health condition.

Medical history. Your doctor will thoroughly check your family history and personal medical history.

Physical examination. Your doctor may require a physical examination based on the symptoms you are experiencing. They are likely to ask you to skip having any dairy products to observe whether that helps in improving your condition. 

Lactose tolerance test. Your doctor may advise you to take this test, which evaluates the ability of your digestive system to absorb lactose. You have to fast for about 8 hours before taking the test. This means that you have to stay away from both food and water. During the test, you will be asked to drink lactose. A few samples of blood will be taken over a span of 2 hours to check your level of blood sugar. If your blood sugar does not increase, it means that you are lactose intolerant.

Hydrogen breath test. This test also requires you to drink lactose. Your breath will then be checked many times for analyzing the hydrogen level in your mouth. High levels of hydrogen may indicate that you are lactose intolerant.

Stool acidity test. This test is used for infants and young children. This test, appropriate only for children, measures the level of acid in the stool. The presence of fatty acids like lactic acid, glucose, etc. in stool indicates lactose intolerance.

Treatment for Lactose Intolerance

Treatment for lactose intolerance involves introducing changes to your daily diet. There is no treatment that can help your body produce more lactase. Previously, people with lactose intolerance were asked to avoid milk and other dairy products altogether.

In contrast, people are now asked to restrict their consumption or try various types of dairy products at different times to understand whether these suit them. 

The following are the dietary changes you can start with.

  • Check how much you can tolerate. Increase the consumption of milk and dairy products slowly and see how much your body can tolerate. Preferably start with the easily digestible milk products like yogurt and cheese and gradually move on to other dairy products.
  • Opt for dairy products with low lactose levels. Like we discussed before, choose yogurt, cottage cheese, and cheese over the other milk products that take comparatively more time to digest. 
  • Combine milk products with other food items. Eat milk products with your meals rather than having them as independent products. For instance, eat a bowl of fruit custard or cheese sandwich rather than having the milk product alone. Also, fresh milk is usually the most difficult to digest. So, you might want to keep it for later.
  • Eat dairy products with naturally lower levels of lactose. These include hard cheese and yogurt.
  • Look for lactose-free milk and milk products. Lactose-free products and those with reduced lactose content are becoming increasingly more popular.
  • Lactase supplements. Your doctor may prescribe a lactase drop or pill to aid in the digestion of milk and milk products. 

Lifestyle Changes for Lactose Intolerance

Living with lactose intolerance may be tricky but not impossible. Once you are aware of all the dairy products that your body has a strong response to, you can discard them completely from your daily diet. You can also try to figure out if these products affect you if only taken in a certain quantity, so that you may continue consuming them with certain restrictions. Make sure you do this only under the guidance of your doctor.

However, people with severe lactose intolerance cannot use the trial and error method. Make sure you also check all the non-dairy products for their ingredients before buying them. Some of these may contain ingredients that lactose-intolerant people cannot consume. In this case, cut down on dairy completely and instead reach out to other healthy options to meet your nutrition goals.

Your daily calcium needs can be met through various foods, such as:

  • Green leafy vegetables like spinach, kale, etc., and broccoli
  • Fishes like salmon and sardine
  • Milk substitutes that do you no harm like soy milk
  • Fruits like oranges and bananas
  • Calcium-rich cereals
  • Dry fruits like almonds, and dried beans

You can also get your daily dose of vitamin D through exposure to the early morning sunrays. Make sure to get more nutrients through food items like eggs, liver, etc. Your doctor may also suggest certain calcium and vitamin D supplements or herbals.

Learn more about Other Digestive Health Issues here


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

Mia Dacumos, MD

Nephrology · Makati Medical Center

Written by Nikita Bhalla · Updated Aug 19, 2022

advertisement iconadvertisement

Was this article helpful?

advertisement iconadvertisement
advertisement iconadvertisement