Dairy Intolerance is Real: Study Says it’s Not in Your Head


Every time you consume dairy, your digestive tract stages a revolt. Your food allergy tests came back negative, so your doctor labeled it as lactose intolerance. “Just take some enzymes and you’ll be fine,” she said. But your dairy woes didn’t stop. Now a research team in New Zealand is here to back you up. You might have dairy intolerance, which they say is a very real thing.

Dairy Intolerance is Real: Study Shows It's Not In Your Head

The Dairy Intolerance Study

“Lots of people suspect that they have some intolerance to dairy foods, but testing shows they aren’t lactose intolerant,” says Dr Amber Milan, a research fellow at the Liggins Institute, University of Auckland. “Our findings show dairy intolerance is a ‘real thing’ with a particular symptom profile – not something that’s just in people’s heads.”

Her team gave 30 healthy young women who reported being dairy intolerant, and a control group of 10 dairy-consuming women, two challenges. The first involved drinking 50 grams of lactose – the amount found in 1 liter of milk – to determine if they had lactose intolerance or not. On a separate visit, the same women drank 750 milliliters (about 3 cups) of standard dairy milk.

The researchers closely tracked each woman’s digestion and metabolism of the milk with a battery of tests. Immediately after the women consumed the milk, and at 30 minute intervals for three hours, the researchers took blood, urine and breath samples, measured their waist, and performed MRI scans. The women also recorded how they felt.

Eat Dairy Free - Your Essential Cookbook for Everyday Meals, Snacks, and Sweets

Lactose Intolerance and Dairy Intolerance Differences

Two distinct symptom patterns emerged. Most notably, the discomfort and other symptoms came on and subsided sooner in the dairy intolerant women. This suggested their underlying issues occurred in the stomach. The lactose intolerant women experienced symptoms over a longer period, which suggested the trouble arose in the small intestines.

The lactose intolerant women experienced the standard symptoms of flatulence, stomach rumbling and cramping. Many of these symptoms were experienced around two hours after drinking the lactose or milk. Their hydrogen breath levels also peaked at two hours, and were up to 10 times above their baseline. Breath hydrogen is a by-product of the gut bacteria digesting lactose that isn’t absorbed by the body.

The dairy intolerant women also experienced acute stomach pain, bloating, flatulence, and distension. However, their symptoms arose within 30 to 60 minutes of dairy consumption. And they showed no signs of lactose malabsorption, such as raised breath hydrogen.

“With these women, it was as if their stomachs weren’t digesting the milk as quickly. We need more research to identify exactly what’s going on, but we know that some nutrients affect the speed of digestion, like fiber or the type of protein; as can the release of hormones, such as insulin and appetite hormones,” says Dr Milan.

The dairy intolerant group also had a drop in blood sugar around the time that they felt most discomfort. But the lactose intolerant and control groups didn’t experience a notable change in blood sugar.

Researchers also identified trends in different chemicals found in the breath of the lactose and dairy intolerant groups. “If further work confirms these differences, it may allow us to create a breath test to determine if people are intolerant to other aspects of dairy, like we currently do for lactose using breath hydrogen,” says Dr Milan.

Go Dairy Free 2nd Edition - The Ultimate Guide and Cookbook for Dairy-Free Living with Over 250 Recipes!

But is it Just a Dairy Intolerance?

There is one missing piece of very important information in this report. Did the researchers test the “dairy intolerant” women for non-IgE mediated allergies? In conditions like allergic eosinophilic esophagitis (EE) and eosinophilic gastroenteritis (EG), symptoms noted by the researchers can be triggered by foods such as dairy.

An intolerance is the inability to properly digest something. Your body angrily acts up when it’s unable to absorb the offending food. But an allergy involves an immune response in which cells in your body are actually attacking the food as if it’s a threat. Symptoms of a non-IgE allergy can range from mild to severe. In some cases, immune responses also have the potential to cause damage and may be more dangerous than an intolerance.

For now, we’re happy the medical community is finally acknowledging that dairy issues are not just black and white. But further studies are needed to identify the “dairy intolerance” sources. There might be many more shades of gray than the researchers anticipated.

Dairy Intolerance is Real: Study Shows It's Not In Your Head

About Author

Alisa is the founder of GoDairyFree.org, Food Editor for Allergic Living magazine, and author of the best-selling dairy-free book, Go Dairy Free: The Guide and Cookbook for Milk Allergies, Lactose Intolerance, and Casein-Free Living, and the new cookbook, Eat Dairy Free: Your Essential Cookbook for Everyday Meals, Snacks, and Sweets. Alisa is also a professional recipe creator and product ambassador for the natural food industry.


  1. I seem to be specifically allergic to cow dairy. Suffered from rhinitis for years, taking antihistamines daily until I cut dairy out of my diet, which resolved the issue. I now find I can consume dairy of other animals – sheep, goat, buffalo, with no problems. I haven’t tried raw organic cow dairy and do wonder if it might be something in the processing of cow dairy that’s different?

    • Hi Nickie, I think almost anything is possible with our food supply. But in terms of allergies, it is the protein that people are reacting to (usually casein and/or whey in milk). The proteins in cow’s milk are slightly different from the proteins in other mammal milks (including sheep, goat, and buffalo). So it is very possible to be allergic to cow’s milk and not allergic to other mammal milks. After all, we aren’t allergic to human milk (we’re mammals, too)!

  2. I found that I am intolerant or allergic to the casein. It took me years to figure this out. But not eating any dairy makes me feel so much better. One of the smaller sides affects I get when I consume cheese is blisters in my mouth. This is very hard not cosuming dairy, but it needs to be this way. I don’t know of any dairy that does not have casein in it.

    • Blisters?! Wow, that would be anti-dairy motivation for me Barbara 🙂 It’s always frustrating when it takes so long to find the solution, but I’m just happy that you did. Casein is the most abundant protein in dairy, so you won’t find any dairy-based products without it.

  3. I’ve so far tested negative to dairy in skin prick and blood test. However if I have any dairy I go red and itch like crazy all over and if I have enough I get hives.

  4. Sabrina Paradis on

    After having my son 3yrs ago everytime i ate 20 min later i would be curled in a ball with stomach pains, then a migraine and vomitting etc. The symptoms would lasts all night! It was so awful i started seeing a natural path and was taken off dairy for 3 weeks. After a week felt incredible and no more symptoms. And after yrs of migraines i dont get them anymore. She put me back on lactose free and i didnt feel good. I got the food sensitivity done and had to consume all foods. All dairy was off the charts. So def Dairy free for me is the best option.

  5. My kiddo reacts between 12 – 24 hours after eating dairy foods, including lactose free foods. There is more than what people believe there to be. My other kiddo reacts with hives. Definitely an allergic reaction for her.

  6. So interesting! My hubby has issues with dairy. We assumed it was lactose intolerance but perhaps it is a dairy intolerance, he feels it very shortly after he eats it.

  7. I’ve been tested and I am intolerant (according to the Dr). I experience these symptoms within 30 minutes of drinking cows milk/ice cream. I can do up to an ounce of hard cheese a couple times a week, but for the most part I stick to dairy-free options.

Leave A Reply