Lactose Intolerance vs Milk Allergy

Written by Huda Fareed-Reviewed by Zoha Matin

Two of the most common disorders related to milk and milk products are lactose intolerance and milk allergy. People tend to get confused between these two. Therefore, it is important to discuss the difference.

Lactose Intolerance

Lactose is a type of natural sugar found in milk and milk products. It is digested and broken down in our bodies by an enzyme called lactase. Normally, lactose is broken down in the small intestine into its constituents; glucose and galactose. In those individuals with a lactose intolerance, this enzyme is absent or is present in low amounts. (1)

Lactose intolerance can be genetically inherited or it can develop later in life due to other health issues. In individuals with a lactose intolerance, lactose is not broken down in the small intestine. It enters the large intestine where it is fermented by the bacteria that naturally reside in the large intestine. In those individual with a lactose intolerance, consuming lactose will produce different types of gases. (1)

These gases lead to various symptoms such as rumbling of the stomach, bloating, gas, diarrhoea, stomach cramps and pain. The severity of symptoms varies from person to person, and can depend on the amount of lactose consumed. (1)

Individuals with a lactose intolerance must generally limit milk (that comes from animal sources), cream, dairy ice cream, yoghurt, cream cheese, cottage cheese and other types of cheese. (2) Some individuals with a milder form of lactose intolerance are able to digest smaller quantities of milk, yogurt and cheese, while others with a severe lactose intolerance can’t digest dairy at all.  

Yogurt has bacteria in it. It helps in digesting lactose. This is why yogurt can be tolerated more easily. (3) Hard and aged cheeses can be digested more easily as well. Whey (the liquid part of milk) contains most of the lactose. It is removed from hard cheese, making it easier to digest. With age, bacteria in cheese digest the lactose. Examples include; Parmesan, Cheddar and Swiss. (4)

If you have a lactose intolerance, you can substitute normal animal-based milks with lactose-free milk, soy milk, almond milk, rice milk, hemp milk and other nut-based milks. Instead of dairy yogurt and cheese, individuals can opt for Kefir, (4) coconut yogurt, soy yogurt and plant-based cheeses.

Individuals with a lactose intolerance are at higher risk for calcium deficiency, so it’s important to focus on consuming other calcium-rich foods such as chia-seeds, almonds, figs, white beans, kale, broccoli, sardines in the diet. (5,6)

If you are diagnosed with a lactose intolerance later in life, there is a chance that after following a strict lactose-free diet for a few weeks, your symptoms might get better. After that, slowly and gradually introduce dairy products in small amounts into the diet. (7) This may allow you to tolerate lactose in small amounts more easily.

Lactose intolerance is not life threatening. It is a digestive system issue that has some uncomfortable symptoms. However, it is easier to manage than a milk allergy. (7)

Milk Allergy

Milk allergy occurs due to the proteins present naturally in milk. Cow’s milk is the most common cause of milk allergy, but milk from goats, buffalo, sheep and other mammals may also cause a reaction. Milk allergy is more common in infants. It is rare in adults but other health factors might play a role in making you allergic to milk in adulthood. (8)

A milk allergy involves our immune system. The immune cells mistakenly consider the milk proteins as harmful substances. Therefore, the immune cells attack by releasing chemicals. This can cause a series of reactions in the body. Some people with a milk allergy have mild symptoms, whereas some have severe life-threatening reactions. (8)

Symptoms of the allergic reaction include nausea, vomiting, diarrhoea, constipation, cramps and bloody stools in infants. Individuals with a milk allergy may also experience reactions on the skin, such as red itchy rashes, hives, and swelling of the lips and face. It might also cause tightness in the throat leading to trouble swallowing. (8,9)

The allergies are only controlled after taking anti-allergies as recommended by a doctor. Babies who are allergic to milk are given an alternate formula that is dairy-free and cow’s milk is omitted from their diet. Mothers who breast feed a milk allergic baby need to avoid milk and milk products. (9,10)

Individuals with a milk allergy must avoid milk and all milk products. Alternatives include plant-based milk and non-dairy products, such as non-dairy ice cream, non-dairy yogurt and non-dairy chocolates. Margarine should be used instead of butter. When eating out, it is best to choose menu items that don’t have milk in the ingredients. Milk proteins are present in many packaged and canned foods. Thus, it is essential to read the labels. If there are traces of milk proteins then that product should be avoided. Use of lactose-free foods is not recommended for people with milk allergy as these products still contain the milk proteins and would cause a reaction. (9,10)

Milk products contain many nutrients that are important for us. People suffering from lactose intolerance or a milk allergy need to consume foods that will provide them with the same nutrients.


  1. NHS Choices. Overview Lactose intolerance. NHS. Published February 25, 2019.
  2. Cleveland Clinic. Lactose Intolerance | Cleveland Clinic. Cleveland Clinic. Published 2019.
  3. Link R. 6 Dairy Foods That Are Naturally Low in Lactose. Healthline. Published February 22, 2017.
  4. Riley K. 7 Dairy Foods That Are Easier to Digest. Experience Life. Published June 12, 2020.
  5. Barhum L. 18 non-dairy calcium-rich foods. Published July 26, 2018.
  6. kidshealth. Lactose Intolerance (for Teens) – KidsHealth. Published 2015.
  7. What Is Lactose Intolerance? WebMD. Published May 5, 2017.
  8. nadolpho. Milk Allergy | Causes, Symptoms & Treatment. ACAAI Public Website. Published March 21, 2019.
  9. Lactose Intolerance vs. Dairy Allergy. WebMD. Published May 5, 2017.
  10. Living With a Milk Allergy. WebMD. Published March 4, 2003.