Dairy Intolerance versus Dairy Allergy

Having a food intolerance is not fun. It can cause abdominal pain, discomfort, and nausea. It also causes embarrassing symptoms like flatulence and diarrhea. Other symptoms linked to food intolerances may include muscle or joint pain, headaches, exhaustion, and even skin symptoms like rashes and eczema.

Whereas lactose intolerance involves the digestive system, an allergy to dairy involves the immune system.

Dairy is just one of those foods that many people seem to be intolerant of. Let’s talk about the main components of milk that people react to: lactose, casein, and whey.

Milk sugar (lactose) intolerance

Lactose is the carbohydrate “milk sugar” naturally found in most dairy products. Lactose intolerance is so common you can buy lactose-free milk in your regular grocery store. Lactose-free products are treated with the enzyme “lactase” that breaks the lactose down before you ingest it. It’s this lactase enzyme that is lacking in most people who are lactose intolerant.

Approximately 65 percent of the human population has a reduced ability to digest lactose.

Lactose intolerance in adulthood is most prevalent in people of East Asian descent, affecting more than 90 percent of adults in some of these communities. Lactose intolerance is also very common in people of West African, Arab, Jewish, Greek, and Italian descent.

The prevalence of lactose intolerance is lowest in populations with a long history of dependence on unfermented milk products as an important food source. For example, only about 5 percent of people of Northern European descent are lactose intolerant. 

– US National Library of Medicine, Lactose Intolerance Statistics

The lactase enzyme is naturally released from your intestine as one of your digestive enzymes. It breaks down the lactose sugar in the gut. When someone doesn’t have enough lactase, the lactose doesn’t get broken down the way it should. Undigested lactose ends up being food for the resident gut microbes. As they ferment the lactose, they create gases that cause bloating, flatulence, pain, and sometimes diarrhea.

Lactose is in dairy but is in lower amounts in fermented dairy (e.g. cheese & yogurt) and butter. Individuals who have difficulty digesting milk can often eat dairy products such as cheese or yogurt without discomfort. These foods are made using fermentation processes that break down much of the lactose in milk.

Steering clear of lactose isn’t that easy as it is added to other foods like baked goods, soups, and sauces. And if you’re taking any medications or supplements, check to see if it’s in there too, as lactose is a common ingredient in them.

If you have symptoms of lactose intolerance, keep an eye on food, medication, and supplement labels.

According to research, “Most individuals with lactose intolerance can tolerate up to 12 grams of lactose, though symptoms became more prominent at doses above 12 grams and appreciable after 24 grams of lactose; 50 grams induced symptoms in the vast majority. A daily divided dose of 24 grams was generally tolerated.”
  • It is also noteworthy that dairy is generally more tolerated when eaten with other foods.
  • Lactose-reduced milk is definitely an option for those who are sensitive, and I use it myself. I buy an ultra-filtered brand which has 14 grams of protein per serving vs only 8 grams of protein found in normal milk (because, protein!).
  • One thing that can help you become more lactose tolerant is to not eliminate it completely from your diet.
  • Unless you have an allergy, the current weight of the evidence supports the net health benefit of dairy consumption.
  • Research shows people who often think they’re extremely lactose intolerant usually aren’t..
  • One meta-analysis found people who claim to be lactose intolerant generally reacted just fine to both lactose and placebo.
  • You might be lactose intolerant, but it’s likely not as bad as you think, provided you keep the serving sizes small.
Milk protein (casein & whey) allergy

Milk is a known, and common, food allergen. In Canada, it is considered a “priority allergen” and must be declared on food labels.

A milk allergy is different from an intolerance. Food allergies are usually present for years, or even a lifetime. Food intolerances can disappear over time, although it’s possible for them to recur if the problem food is eaten regularly again.

An allergic reaction to food involves an exaggerated immune system response. Symptoms include rash, hives, tightness in the throat, wheezing, and in extreme cases, death can result.

It’s estimated that 3-7% of children and about 2% of adults suffer from a food allergy. – Precision Nutrition: All About Food Sensitivities

So, what are the allergens in milk? You’ve heard of “curds and whey?” Well, these are the two main proteins in milk. The solid bits are the curds (made of casein), and the liquid is the dissolved whey.

Unlike lactose intolerance, casein and whey can cause an actual immune response to the milk proteins your immune system identifies as harmful, triggering the production of immunoglobulin E (IgE) antibodies to neutralize the protein (allergen). Your body releases histamine and other chemicals, causing a range of allergic signs and symptoms.

Like lactose, these allergenic milk proteins can be found in other products too. They’re not just in dairy but are often in protein powders as well (e.g. “whey” protein powders).

Like lactose intolerance, if you’re allergic to casein and whey keep an eye on labels so you can avoid these. You’ll know if you’re allergic or intolerant based on the type of reaction you experience.


If you get gassy, bloated, or diarrhea after eating dairy, you may have lactose intolerance. If you get hives, rashes, or wheezing, then you may be allergic to casein and/or whey.

While dairy may be an entire food group, it is not an essential nutrient. All the nutrients in dairy are available in other foods but there are many health benefits to dairy.

Dairy products can be an excellent source of calcium and protein, and studies show that it can be very satiating and help dieters to lose more weight.


Recipe (Dairy-free): Chocolate Ice “Cream”

Serves 2

3 bananas, sliced and frozen
2 tsp cacao powder, unsweetened
1 tbsp almond butter


  • Place frozen bananas in food processor and blend until smooth (a few minutes). You may have to stop a few times to scrape the sides.
  • Add cacao powder and almond butter and blend until mixed well.
  • Serve & enjoy!
  • Tip: You can make this in advance and freeze in an airtight container.




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If you decide to (or have already) removed dairy from your diet, or if you’ve recently resumed having dairy, let me know your experience in the comments below.

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