Lactose intolerance & milk allergy: what is the difference?

Lactose intolerance and dairy allergy are not the same thing. Learn common symptoms for each and how to avoid hidden sources of dairy in your diet.

Lactose intolerance and dairy allergy are not the same things. Although both require removing certain dairy products from your diet, a milk allergy is a severe reaction to the protein, while lactose intolerance is a digestive reaction to the milk sugar. Learn common symptoms for each and how to avoid hidden sources of dairy in your diet.

Difference between lactose intolerance and milk allergy 

Lactose intolerance and milk allergy sound like the same thing, and both require eliminating or limiting dairy, but they have important differences. 

Lactose intolerance

Lactose intolerance is an inability to fully digest the main carbohydrate found in cow’s dairy, called lactose (1). This occurs when there isn’t enough production of the lactase enzyme (a protein that speeds up a reaction in the body). Lactase is an enzyme that breaks down lactose into single sugar molecules that can be easily absorbed into your bloodstream and used as energy (2). 

When milk carbohydrate doesn’t get properly digested, it stays in your digestive tract, where it gets fermented by bacteria that live there. This results in uncomfortable symptoms such as diarrhea, gas, and bloating after eating or drinking dairy products containing lactose.  

Milk allergy 

A cow's milk allergy is in response to the proteins found in cow’s milk. It results from abnormal immune activity (3). If you have an allergy to milk, your immune system will identify certain proteins as harmful. 

When you consume dairy, your immune system sends protective “troops” (IgE antibodies) to help neutralize the protein (allergen). So whenever you eat these proteins, your body will signal to send chemicals such as histamine which leads to allergic symptoms. 

Symptoms of lactose intolerance and milk allergy

Lactose intolerance symptoms

Lactose intolerance is more common in people originally from certain parts of the world like East Asia, West Africa, southern Europe where dairy products historically haven't been as common as in countries in Northern Europe (4). The chance of developing lactose intolerance also tends to increase with age. 

Symptoms of lactose intolerance usually pop up within about 30 minute to a few hours of eating or drinking something that contains lactose. Symptoms are mainly digestive concerns such as:

  • Gas
  • Bloating
  • Diarrhea 
  • Stomach cramps and rumbling 
  • Feeling sick to your stomach (5)

Milk allergy 

Milk is one of the most common food allergens. It occurs most often in infants and children but can develop at any age (3). 

Symptoms present themselves within a short period of time after eating or drinking something that contains milk or milk protein. Symptoms can be dangerous and include:

  • Anaphylaxis: a potentially life-threatening reaction that can cause shortness of breath and can send the body into shock.* 
  • Stomach upset
  • Vomiting
  • Hives 
  • Blood in stool (6)

*Anaphylaxis is a medical emergency and requires treatment with an adrenaline shot (such as EpiPen) or a trip to the emergency room. If you think you may be experiencing a severe allergic reaction to milk or any other substance, contact your local emergency line. 

Lactose intolerance and milk allergy: what can you eat?

There’s no cure for lactose intolerance or milk allergy so the best thing to do is limit (for lactose intolerance) or avoid milk-containing products. Thankfully there are many lactose-free and plant-based dairy alternatives available these days. 

For lactose intolerance, you may be able to have small amounts of dairy and not have symptoms. You can also try lactase enzymes to take with dairy. Just make sure to contact your physician before starting them. As for milk allergy, it's important to avoid all dairy containing foods and drinks. 

Food that are safe to eat for those with lactose intolerance or milk allergy are for example: 

  • Breads, grains, potato: milk-free breads, milk-free cereals, potatoes, grains. 
  • Meat: fresh baked, broiled, or roasted beef, pork, chicken, turkey, fish.
  • Plant-based protein: tofu (prepared without milk products), beans, lentils without milk or milk products. 
  • Vegetables: fresh, frozen or canned without milk or milk products. 
  • Fruits: fresh, frozen, or canned fruits and juices. 
  • Fats: vegetable oil, peanut butter (without milk solids), nuts, seeds. 
  • Dairy alternatives made out of soy, almond, rice, oat, hazelnut, coconut, cashew. Lactose-free cow’s milk - only for lactose intolerance, not milk allergy (6). 

Detect dairy in your common dishes (and foods)

Milk is typically found in creams, cheese, butter, ice cream, and yogurt. Keep in mind that when a food is labeled as “non dairy” it won’t contain ingredients such as milk or cream, but the food can have other milk containing ingredients. When having an allergy or intolerance make sure to always read the nutrition label. 

When avoiding milk, watch for these ingredients:

  • Butter, artificial butter flavor, Ghee 
  • Casein, casein hydrolysates, caseinates
  • Cheese, cottage cheese
  • Cream, half and half 
  • Hydrolysates (casein, milk protein, why, whey protein)
  • Lactoglobulin, lactoferrin
  • Lactose, lactulose
  • Milk (whole, low-fat, nonfat, skim, goat’s, milk protein, solids, malted, condensed, evaporated, dry)
  • Nougat
  • Rennet casein 
  • Yogurt 
  • Sour cream 
  • Whey (6)

Some more sneaky sources include brown sugar flavoring, caramel flavoring, chocolate, high protein flours, lunch meat, and margarine. 

Final scoop 

Unless you have a dairy allergy or intolerance, there are many good reasons to continue including dairy in your diet. It's a great source of protein, vitamins, and minerals which can help keep bone and teeth strong and promote muscle and growth. 

If you think you may have lactose intolerance or a milk allergy, contact your physician. They can assess your symptoms, family history, and eating habits and possibly perform a physical exam and tests.

If it's time to ditch the dairy, let a customizable nutrition app guide you so that you get a variety of nutrients. Start off with these delicious recipes. You won’t even know the milk is missing! 

Banana bread

Protein Packed Oatmeal

Banana Oats

6 references (hide)

All of the content and media on Lifesum is created and published for information purposes only. It is not intended to be used as a substitute for medical advice or treatment. Users should always consult with a doctor or other health care professional for medical advice.

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