Should people with celiac disease avoid diary?

Should people with celiac disease avoid diary?

To eat dairy or not to eat dairy. This is a hot topic of debate in the celiac disease world. If you’ve been on any online support groups for people eating gluten free, dairy free seems to come up almost as often. And why is that? Let’s dive into why people may need to eat this way.

Sometimes when people go on a gluten free diet, gut symptoms persist. This happens in an estimated 47% of people (1)! There are many reasons for this, you can read more in my article about this here. One possible reason for persistent symptoms may be a cow’s milk intolerance, specifically an issue with a protein called casein.

What the research says about casein and celiac disease

There was a study in 2007 that found 50% of people with celiac disease were also intolerant to casein (2). This specific protein found in cow’s milk caused an inflammatory reaction in the gut that was similar to the inflammation seen with celiac disease, in half of the participants.

The study took 20 people with celiac disease, 15 healthy controls and exposed them to gluten and to cow’s milk protein. Ten out of the 20 people with celiac disease showed a significant inflammatory response to both gluten and cow’s milk. The researchers went further to test whether casein or α-lactalbumin was the issue. The results found casein to be the culprit.

celiac disease, registered dietitian, clear focus nutrition, IBS, bloat, pain, gut symptoms, gluten intolerance

What is the problem with dairy for people with celiac disease?

The problem with diary can be one of two issues: lactose or casein.

Lactase and inability to digest the milk sugar

Lactose is a type of carbohydrate, or sugar, found in milk and dairy products. Normally the enzyme that is responsible for digesting or breaking down lactose, called lactase, in the intestine in found on the tips of the villi. If someone has intestinal damage as in with active celiac disease, the process will not work properly, if at all.

When that undigested milk sugar makes its way into large intestine, the bacteria in the gut have a party! They love sugar, eat it up very quickly and as a result produce a large amount of gas. This gas can contribute to bloating, cramping, diarrhea and pain some people experience.

It can be helpful to remove lactose for a few weeks at the beginning of the healing process to try to minimize symptoms. However, some people actually regain the ability to digest lactose once the villi and intestinal lining heal. So don’t give up on lactose completely, it may just be a temporary issue.

Casein protein and immune response

Sometimes the immune system can get confused with the protein casein, in a similar way that is does to gluten with celiac disease.

With active celiac disease, the lining of the intestine is damaged which allows large protein fragments to make their way into the bloodstream where they have no business being. The immune system can potentially identify these proteins as potential viruses or bacteria and develop antibodies against them. In the future, when that protein is consumed, the immune system acts to defend the body by rapidly producing those antibodies in defense. This is how celiac disease forms and research suggests this can happen to other proteins as well.

Casein is a common issue because it is structurally similar to gliadin, a protein fraction of gluten. It is also resistent to digestion, similar to gliadin, which means it has a better chance of getting into the bloodstream if the gut lining is “leaky”.

To read more in depth about how celiac disease is related to leaky gut and the immune system read here.  Some studies attribute casein or cow’s milk intolerance to a potential reason of why some patients do not achieve full intestinal recovery.

celiac disease, registered dietitian, clear focus nutrition, IBS, bloat, pain, gut symptoms, gluten intolerance

How do I know if I’m casein intolerant?

Classic allergies can be tested for with an antibody called IgE. Non-classic food allergies are difficult to evaluate. The only way to test them currently, is to remove a suspect protein from the diet for a certain period of time and then challenge it to evaluate symptoms.  This may be a temporary issue or it may be a long term one. For some people it may not be an issue at all.

Talk to your doctor or other health care professional for advice if you think dairy might be an issue for you.

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What do I eat without dairy and gluten?

Focus on keeping meals simple and being creative with adding flavours.

Here’s an easy tip: assemble meals with building blocks.  Vegetables, protein, complex carbohydrates and add on a dairy free/gluten free sauce for flavour.  Add in fruit and plant based milk alternatives like almond, soy, coconut, pea, hemp or oat based beverages.

Try some of these: make your own balsamic vinaigrette, honey mustard sauce, peanut thai sauce, basil or cilantro pesto, tomato sauce or roasted butternut squash sauce.

Stay tuned this month for tips on replacing cheese.

As with any big dietary change, it is wise to speak to a registered dietitian to ensure you are meeting your nutrition needs.

To learn more about how I can help with persistent gut issues, read more about me.


  1. Sylvester, J.,A., Graff, L.,A., Rigaux, L,, Bernstein, C.,N., Leffler, D.,A, Kelly, C.,P., Walker, J.,R., Duerksen, D.,R.(2017). Symptoms of functional intestinal disorders are common in patients with celiac disease following transition to a gluten-free diet. Digestive Diseases and Sciences, 62(9): 2449-2454.
  2. Kristjansson, G., Venge, P., & Hallgren, R (2007). Mucosal reactivity to cow’s milk protein in coeliac disease. Clinical and Experimental Immunology 147: 449-455.


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