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24 Dec

Dairy Intolerance: What It Is and How to Determine If You Have It

Dairy IntoleranceI often say that “dairy is fine and even healthy if you tolerate it.” But what exactly does that mean? How do you know if it’s “not okay”? You could be reacting poorly to the lactose, the casein, the whey, or all of it. You could just ditch all dairy forever more and be perfectly fine – but you shouldn’t eliminate a food group, especially one as delicious, nutrient-dense, and potentially rewarding as dairy, unless you absolutely must. Plus, it’s just good to know what you can and cannot tolerate. You don’t want to tiptoe through life, scared of food because you’ve never taken the time to determine your ability to tolerate it. You want to be empowered with knowledge and venture forth boldly – or carefully, if caution is warranted – through the cheese aisle.

The most common dairy components that people have trouble with are lactose and casein, with intolerance to each presenting differently. Let’s look at both.

Lactose Intolerance

Lactose intolerance occurs when people stop making lactase, the digestive enzyme located along the small intestinal wall that breaks lactose into glucose and galactose for easy digestion. This usually occurs around the age of four or five (lactose intolerance is incredibly rare in infants, for obvious reasons). Without lactase, lactose is instead metabolized by bacteria, which can cause stomach upset, flatulence, diarrhea, bloating, nausea, and a host of familiar but unwelcome gastrointestinal symptoms also seen in FODMAPs intolerance. In fact, the disaccharide lactose is a FODMAP. Lactose intolerance generally isn’t life threatening (unless you’re a baby who depends on a lactose-containing food) but it is annoying and can make life difficult and unpleasant.

Causes: Most lactose intolerance develops because people stop producing lactase after weaning. No more breast milk, no more need to expend the energy necessary to produce lactase. This is usually genetically determined, and people with milk-drinking ancestry are far more likely to possess the gene(s) for lactase persistence (it takes just one copy to keep making lactase into adulthood).

Some lactose intolerance is transient and stems from damage to the epithelial cells lining the intestine, which are responsible for producing lactase in the gut. If something like viral gastroenteritis or food poisoning damages enough gut lining, lactase production and thus lactose digestion may be hampered for the duration of the sickness.

Other lactose intolerance stems from gut dysbiosis. Many gut bacteria, particularly Lactobacillus, produce lactase that help the host (that’s us) break down and absorb lactose. If your gut flora composition is missing the right species or overcrowded with the wrong ones, lactase production may suffer.

Prevalence: About 75% of the world’s population shows decreased lactase production into adulthood, but distribution varies wildly by ethnicity and nation. Looking at this global map is probably a better way to understand the prevalence of lactose intolerance than throwing out a single number. Among Northern Europeans, who have a long history of dairy consumption, prevalence is around 5%. In most of Sub Saharan Africa, where dairy is rarely consumed, lactose intolerance nears or surpasses 90% prevalence.

How to determine: The medical profession uses two main tests for determining lactose intolerance. Both involve the test subject consuming a lactose-rich drink. The hydrogen breath test measures the amount of hydrogen in your breath. If you’re unable to digest lactose, any lactose you consume will make it to the colon to be digested by hydrogen-producing bacteria; this hydrogen will show up in your breath. Another option is the blood glucose test. If your glucose doesn’t go up after eating lactose, you’re not cleaving it into digestible monosaccharides and you are probably lactose intolerant.

At home, a simple test is the oral challenge: eat some lactose powder that you’ve mixed into water and see if any of the previously mentioned symptoms arise. Start with 25 grams of lactose, which is the amount found in two big glasses of milk. I would advise against using milk itself, since milk contains both whey and casein, and it might be difficult to parse which component you’re responding to. Even though lactose powder is a processed, isolate, refined component, it doesn’t really matter much since whole food lactose is identical.

Dairy Protein Intolerance

A dairy protein (whey or, more commonly, casein) intolerance is different than a full-blown allergy. In an allergy, consumption of the offending food elicits an immediate, acute, unmistakable immune response. You might get severely plugged sinuses, itchy skin, hives or rashes, hypotension, diarrhea, vomiting, an elevated heart rate, and have difficulty breathing. Tests can confirm it but you’ll probably already know you’re allergic. If a swig of milk causes anaphylaxis, you don’t need a post on MDA telling you to drop it for 30 days and reintroduce it. You’re already in the know.

Intolerances to the proteins in dairy are a bit more confusing. Some of the symptoms are similar to, if milder than those of allergic reactions. For some people, it manifests as constipation. For others, diarrhea. Still others get tingly fingers, joint pain, and a foggy head. Whatever the symptoms of a dairy protein intolerance, they usually take longer to appear, making identification difficult. Plus, little scientific consensus exists on the nature of dairy protein intolerance. There are no universally accepted lab tests and few medical professionals will be able to help. Casein seems to be the most common dairy protein people are sensitive to; it’s far more rare for whey to be an issue.

Prevalence: According to population-based studies, the prevalence of cow’s milk protein allergy ranges from 0.25 to 4.9% of young children. It’s less prevalent among adults and older kids. Official numbers for milk protein intolerance prevalence are unknown because the condition itself is relatively unknown in the medical community.

How to Determine: You can do skin prick tests or shell out the dough for expensive food sensitivity lab results (that may not even tell you anything definitive), but the gold standard remains the food challenge: strict avoidance of the suspected food until symptoms subside followed by an oral challenge.

It seems like the simplest way to perform an oral challenge would be to eat some whey isolate or casein protein powder. After all, that’s just whey or casein, right? That may work, but I don’t think the results would necessarily transfer over to other sources of whey (like milk) or casein (like Greek yogurt). Unfortunately, the way we process dairy seems to change the structure of the proteins and, thus, their potential for reactivity. Fermentation of yogurt alters protein peptides. Heat treatment has been shown to make casein more allergenic and resistant to digestion by infants, while kids with cow milk allergy, for example, can tolerate baked milk fairly well – although that may be a function of quantity since “baked milk” is shorthand for “baked goods containing milk,” which are mostly flour and sugar, not milk protein.

So, given the fluid nature of dairy protein in response to processing, you may have to determine your tolerance of specific types of dairy to get an accurate picture.

The basic idea is to remove all dairy for at least 30 days. This gives your body a reprieve that, according to some, is necessary to re-sensitize your body to potentially problematic proteins. If dairy proteins are inducing a low-level inflammatory state that lasts for days or weeks and muddles the message, you need a solid chunk of time without any for reintroduction to provide accurate information. So skip the cheese, the milk, the cream, even the butter (I’m sorry) for 30 days if you suspect you have a dairy intolerance. Then, introduce dairy foods one by one, giving yourself two or three days to ensure lack of latent response before trying a new one.

Casein-rich foods: most cheeses, Greek yogurt (yogurt with the whey drained), cottage cheese, casein protein powder

Whey-rich foods: ricotta, whey protein powder

Foods with casein and whey: milk, yogurt, kefir, butter

Causes: A major, and in my opinion likely, candidate for the cause of dairy protein intolerance is intestinal permeability, or leaky gut. An overly permeable intestine (all intestines are permeable to a certain degree; it’s excessive permeability that’s the main issue) allows protein fragments from the digestive tract into the bloodstream. When the immune system identifies these errant proteins as invaders, it does what it does in response to any other invading pathogen: mount an attack and fortify the body’s defenses by releasing histamine (which tries to get rid of the “pathogen” by inducing diarrhea, sneezing, runny nose, watery eyes, and all the other symptoms you might get from an allergic or intolerance reaction). In a perfect world, casein may not be inflammatory in and of itself, but its presence in the bloodstream can invite an inflammatory response.

What to Do

Say you’ve figured out you have an intolerance but you still want to eat dairy. What can you do?

If it’s lactose intolerance, you can beat that. Chris Kresser explains how to go about it.

Try different kinds of dairy. Try raw. Try fermented. Try grass-fed. Try organic. Try sheep. Try goat. Try camel, even. Try hard cheese, aged cheese, soft cheese. Try yogurt or kefir. Try ghee. Try A2 dairy. In other words, you may not be intolerant of all forms of dairy.

Fix your gut; make it less permeable. Easier said than done, I know. Here are some things to try or track to tighten up those tight junctions:

  • Be vitamin D replete. Activation of the vitamin D receptors on the intestinal wall inhibit intestinal permeability. If you lack adequate vitamin D, your gut permeability may increase, leaving you open to dairy intolerance.
  • Eat fermented foods and/or probiotics. One study (highlighted by a reader last week; hat tip to you) showed that adding a probiotic strain to dairy could inhibit intestinal permeability.
  • Feed your gut flora with prebiotics. Prebiotics like inulin and resistant starch (which I discussed here) have been shown to increase butyrate production and reduce intestinal permeability.
  • Get a handle on stress (or change how you approach it). Stress can increase intestinal permeability and disrupt your digestion.
  • Exercise regularly. This can attenuate the stress-induced permeability.
  • Watch your omega-6 intake and be sure to get your omega-3s. Omega-6 PUFAs lower occludin in tight junctions, making them not so, how you say, tight. DHA had the opposite effect.

The main message here is: Be methodical so you know what’s really going on. This is where The Primal Blueprint 90-Day Journal will really come in handy.

What do you think, readers? Do you suspect you have a problem with dairy? Think you’ll give it a shot and try to get to the bottom of it?

Thanks for reading, all!

You want comments? We got comments:

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  1. I think the issue so many people have with the diary component of the Primal lifestyle is because many people find this way of eating after becoming severely health compromised. After years of throwing wheat and sugar down our throats, it’s probably not possible for there not to be moderate to severely major gut permeability issues. I think for Primal newbies, it may be best to look at increased gut permeability as the NORM, rather than the rare exception.

    Sean wrote on December 26th, 2013
  2. We found my 4 year old to be severely allergic to dairy when he was old enough for solids. We tried yogurt and he had an anaphylactic reaction. Soon after this discovery my mother had an allergy test at 61 years old and they said she was so allergic to casein she should carry an epi pen. She said all she noticed was sinus issues once in a while after consuming dairy. I went Paleo in January and was dairy-free for several months. I got pregnant in May and thought I would add back some dairy. I started getting migraines on and off. I finally made the association that dairy is now giving me migraines. I also realized that I have only managed to carry a pregnancy past the first trimester when off dairy. Not sure if the dairy issue will go away once the baby is born or if I have been like my mom and was never really aware I had a dairy allergy until now.

    Kandy wrote on December 26th, 2013
  3. I had thought that dairy caused acne for me, but now I’m not sure. I recently read something that said that it takes up to two months for a pimple to form. However, people claim that they break out in as little as a day from eating dairy. If it’s the former, it would be much harder to tell.

    Justin wrote on December 27th, 2013
    • It is confusing, Justin, but I just think of all the people–including me–who have broken out in a rash or hives after consuming something that doesn’t agree with their system. They can pop up within minutes, hours or a couple of days, so perhaps the kind of breakouts people get from dairy are different than the ‘average, normal’ pimple that’s usually caused by bacteria and sebum build-up? I don’t know for sure because of the conflicting info you referred to, but it’s just a thought….

      Tee Dee wrote on January 5th, 2014
  4. I have celiac disease and also have problems with milk. The strange thing is that I can drink milk if it has been scalded, or heated to boiling. I can eat some yogurt brands and some cheese brands, but not others. I haven’t fully figured out why. In the case of cheese and yogurt, I think it has to do with how the milk is treated before making the product. I am guessing that some of the brands of cheese and yogurt use heated milk which denatures the proteins prior to the culturing and curing processes. My guess it that when the proteins are denatured then I don’t react to the epitopes as they a have changed or altered 3-D conformation. This would also potentially explain my non-reaction to scalded to milk.

    Ed wrote on December 27th, 2013
  5. Nice to have a post that clearly indicates the difference between a dairy allergy and an intolerance to either lactose or the proteins.
    I have a casein allergy – I get hives and breathing issues (asthma like rather than full blown anaphalaxis), and I can tell if you stirred my cup of coffee with the same spoon you stirred your milk-containing one within minutes.
    I do suspect a huge amount of my allergy to milk is due to what the animals are fed and how the milk is treated… I was fine with my 100% grass-fed (or rather 100% natural fed as goats are browsers not grazers and my goats ate more than just grass! what they didn’t eat is lots of grains and soy), raw goats milk from the goats I kept as a teen, but I react to commercially produced (and pasteurized) goats milk. I also react to all cows milk. No idea if I react to raw cows milk as I have never tried that (we only kept sheep and goats on my parents farm). I just know that from a young child I had an aversion to commercial cows milk, yet I loved the raw goats milk.
    Sadly it is impossible to buy raw dairy in Canada so I can’t test to see if it is the raw or pasteurized that is affecting me.
    I didn’t develop my allergy until after I had moved away from my parents farm and was eating/drinking commercial (cows) dairy that was pasteurized.
    I suspect my allergies are a combination of the food that commercial dairy animals are fed, but also that the pasteurization process is denaturing the proteins and changing it into one that my immune system is reacting to.

    salixisme wrote on December 27th, 2013
    • Everyone that has issues with milk should read the book “The Devil In The Milk”. Industry doesn’t want people to know that most of the problems caused by dairy is due to a genetic mutation in European cattle. The mutation is the “A1 beta casein” gene, originally all cattle had A2/A2 genes. Scientists have known about this for many years and the data collected by the world health organization shows the significant difference in the health of countries that don’t have European cattle. Do yourselves a favor and do a search on the A1 beta casein gene. Also the author of the book “The Devil In the Milk” profesor Keith Woodford has a great youtube video. You will be at least very surprised this hasn’t gotten more attention.

      Allen wrote on December 13th, 2015
  6. Great advice. I’ve found that probiotics can go a long way towards helping with this too.

    Rita wrote on December 28th, 2013
  7. Lactose free cheese- gruyere, most aged gouda. Beemster makes gouda labeled lactose free in a few varieties. My husband tolerates no lactose, and discovering these has really opened up a lot of meal options!

    Sarah E wrote on December 28th, 2013
  8. One important thing to note about lactose intolerance missing from this post. The chemical processes that occur in making cheese, yogurt, etc. from milk eliminate most of the lactose. So even if you are lactose intolerant, odds are it’s just plain milk that will cause unpleasant symptoms. You should have no trouble at all eating other dairy products.

    Mark P wrote on January 10th, 2014
  9. The article and comments have been so helpful — many thanks! Over the past 5 years especially I’ve experienced reactions to gluten, wheat, oats, quinoa, casein (I felt like cottage cheese tried to kill me last week with hives, nausea, trouble breathing, achiness, etc. Day 6 and hives are just starting to clear.) I thought I was doing fine with organic milk, butter and cream, but I have gotten scalp pimples/cysts so extra thanks to the person commenting about that previously…I have thrown out/switched shampoos/coniditioners multiple times thinking it was an ingredient in those…never thought dairy! Also get severe multi day migraines from MSG, caramel, etc and swollen face/eyelids/fingers from a little bit of table salt, and achey joints from beef. It all seemed so random before, but now the postings for dairy allergy testing and info about corn allergies and acid in beef are helping me connect the dots now. Not to mention the possibility of a casein allergy vs lactose intolerance. Can’t say thanks enough! Couple questions though — how can I amp up probiotics if I react from yogurt and kefir? And any recommendations for prebiotics/fermented foods that don’t have salt added? (I do ok with sea salt, but not sodium, not even braggs amino acids.)

    TC wrote on February 24th, 2014
    • Here’s the list that I am taking to help fix my gut:

      Primal Blueprint Primal Flora
      Sedona Labs iFlora
      Primal Defense Ultra
      Prescript Assist Probiotic
      AOR Probiotic-3

      James N. wrote on June 22nd, 2014
  10. What do sinus infections, frequent colds and flus, athlete’s foot, midsection belly fat, leaky gut, dandruff, jock itch, unexplained gas/bloating, lethargy, and mild headache all have in common? For myself, the answer is a1 casein from the black-and-white Holstein cow and it is by far much worse than the gluten in wheat. The A2 casein doesn’t do any of this, so I can tolerate butter, sheep and goat dairy without any issues. And another confounding factor to all of this is that the a1 casein problem can be confused with lactose intolerance.

    The good news is that I am now starting to see some relief now from this messed up situation with the addition of probiotics and resistant starch from potatoes, sprouted brown rice, split peas, white Navy beans, Anasazi beans,sprouted lentils, non-GMO lime treated corn tortillas, and raw to lightly cooked oatmeal. .

    James N. wrote on June 22nd, 2014
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    where to get hcg wrote on July 9th, 2014
  12. My hubs and I are both Scandinavian, and I am always annoyed by people who complain about the evils of consuming dairy. (Mostly vegans) How is it that breastmilk is the world’s most perfect food, but cow’s milk is “cow pus”, disgusting, and unhealthy? I know the formulation of sugar, protein, and fat is different than breastmilk, but jeez!

    For our family, things like heavy cream, yogurt, and grass-fed butter are a HUGE part of our overall health. We make yogurt and kefir regularly. If you find you are sensitive to dairy, try taking digestive enzymes before you give up on it completely. Dairy foods are packed with nutrition, doubly so if you can find grass-fed!

    Juniper wrote on September 30th, 2014
  13. Just to bring an awareness to symptoms of a casein intolerance, here’s what I typically experience after the ingestion of dairy:

    Immediately: sinuses start to act up within about fifteen minutes, my ears begin to fill with fluid. A few hours later I can get a sore throat, and start to feel very sleeps and begin to nod off and slur when I talk.

    Day One: the next day, my lips will be very swollen and it is difficult to wake up. I am very disoriented and thoughts are very confused. I can be very irritable and get angry for no real reason. My senses are heightened and noises drive me crazy. I will experience some gastric upset, mainly diarrhea by mid day.

    Day Two: very lethargic and hard to get motivated. I have intense aching in my joints that can bring me to tears, it hurts so badly. I feel like I want to rip muscles and joints out of my body! I could literally stay in bed the entire day. The only thing I’ve found that helps is a combo of some caffeine and ibuprofen. Gastric upset continues.

    Day Three: just “off-kilter” and thoughts don’t connect well. Gastric issues continue but lessen, and the aching is less.

    This takes about three days to leave my system, and honestly those three days are hell. I avoid it at all costs, because it will literally destroy my life if not kept under control. An elimination diet identified this issue.

    Carey wrote on January 30th, 2015
  14. Thanks Carey!

    I really appreciate the eloquent response. Do you know how much casein you feel you have to consume for the symptoms you mentioned to be very evident? And what foods (be as specific as you can and like!) you find them in? I am okay with whey and cream… But something, -I hope it’s identifiable- will make me just feel (and appear) awful every once in a while. But it seems to be hit or miss, out of nowhere.

    Again, any info is appreciated.



    Ann wrote on January 30th, 2015
  15. P.S. Especially the swollen lip and eyes. What IS that all about? It’s like I got stung by something in my sleep.

    Ann wrote on January 30th, 2015
  16. I have a symptom I don’t see listed, or in the comments. About half an hour after having a milk product, I want to stop using any senses: seeing, hearing, feeling and listening. I don’t want to be touched, and I don’t want to move.
    In addition, if I’ve had milk, cheese, yogurt (I haven’t tried Greed) or margarine (except vegan), I get bloating, diarrhea otherwise just loose bowel, possibly swollen joints but I’m not sure, poor co-ordination of muscle movements, and acid reflux when I lie down. When I cut out all milk products and anything with whey (but casein in soy cheese is ok), the reflux remains, but otherwise I feel fine. I’ve tried a cheese labeled “lactose free”, but still got loose bowel and bloating.
    What test do you recommend I take to find out if I still have to avoid all milk products, especially to avoid the first problem mentioned?

    Anne Eriksen wrote on April 30th, 2015

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