Lactose Intolerance: Often A Result of ‘Silent’ Wheat-Derived Bowel Disease

In the comments to last week’s post on food toxins and bowel disease, I stated that, “People with bowel problems will usually do well to avoid dairy proteins, but my belief is that people with healthy bowels can usually manage dairy.”

Today, Peter links to some evidence for that proposition.

In 2005 a group led by Antonio Gasbarrini at Catholic University in Rome studied patients who experienced diarrhea and bloating after dairy consumption. They gave all patients an H2-lactose breath test, which tests the ability of the small intestine to digest the milk sugar lactose, and tests for celiac disease antibodies.

The found that 24% of those with lactose malabsorption, but only 2% of those who could digest lactose, tested positive for celiac disease antibodies. [1] It appears that destruction of the small intestine by wheat is a leading cause of inability to digest lactose – the prerequisite for lactose intolerance.

A 2008 follow-up study showed that when these patients gave up wheat and other gluten-containing grains, they recovered the ability to digest lactose:

The present study shows that a large proportion of CD patients experience a regression of lactose malabsorption after receiving a gluten-free diet. This may be related to normalization of the brush border with an improvement of lactase enzyme activity. LBT should be performed after 12 months in CD patients on a gluten-free diet in order to assess the persistence/disappearance of lactose malabsorption, thus avoiding an unnecessary lactose-free diet. [2]

Now these papers deal only with lactose malabsorption, not problems with partially digested cow casein peptides, which are the most important cause of difficulties from dairy.  So they don’t prove that dairy is safe for those who don’t eat grains and have healthy bowels.

However, they do give a bit of encouragement to those of us who are loathe to follow Loren Cordain’s advice to give up dairy.  

[1] Ojetti V et al. High prevalence of celiac disease in patients with lactose intolerance. Digestion. 2005;71(2):106-10.

[2] Ojetti V et al. Regression of lactose malabsorption in coeliac patients after receiving a gluten-free diet. Scand J Gastroenterol. 2008;43(2):174-7.

Leave a comment ?


  1. I can’t wait to get your book because I can’t imagine a diet without any grains or dairy, but I’m willing to learn.

  2. My n=1 story meshes with this. I used to get horrible migraines and severe stomach problems after I ate dairy, so I stopped eating dairy and it lessened but didn’t solve all my problems. I discovered paleo/primal about 10 months ago, cut out all grains and dairy for a month (Cordain style paleo), and then reintroduced dairy a la Kurt Harris. Now almost a year later I seem to have no problems with dairy, but a little bit of gluten still has nasty effects.

    • Great story, Katie. This accords with my reading of the biology: for casein to provoke a damaging reaction, it has to penetrate the mucosal barrier and get into the body. This shouldn’t happen in a healthy bowel. Wheat peptides can themselves induce intestinal permeability (gluten) or transport themselves through intestinal cells into the body by transcytosis (WGA), but I haven’t seen reports that casein peptides do this. So they need the bowel to be damaged by some other means before they cause systemic problems.

      Just to be safe, I restrict myself to reduced-protein dairy products — heavy cream has about half the protein of whole milk, butter about half the protein of heavy cream — and fermented dairy products like whole milk yogurt and cheeses. I think this is a good compromise for people with reasonably good bowel health. Those with severely damaged bowels may need to limit themselves to clarified butter. Too bad!

  3. Yup Paul, you are once again right. No more lactose problems for my husband or I. No wheat – No problems. It’s so simple, yet there are still non-believers out there.

  4. This was true for my BIL. After several months of a very low carb diet he regained his ability to eat cheese without taking Lactaid pills.

  5. Paul, been meaning to ask what you thought of this mystery — in case you happen to eyeball this older post and have a few seconds. (I figure I should catch you before you decide at some point that responding to all of us is too much work!)

    My wife (100% Korean ancestry) has been “lactose intolerant” for nearly 20 years, and avoided dairy accordingly. I find the diagnosis suspect.

    She has no effects from regular skim milk daily in coffee (1/8-1/4 cup of skim milk), despite its high lactose; she has serious stomach and bowel effects from, say, eating pancakes made with heavy cream (despite its low lactose), or eating a moderate amount of cheese — even “naturally lactose-free” Finlandia Swiss; Lactaid never worked for her.

    Moreover — and most curious to me — she loses the “intolerance” while pregnant. She can eat dairy with no issues for the duration of the pregnancy. But after delivery? Right back on the intolerance wagon.

    You mentioned “problems with partially digested cow casein peptides” in the post above — I wonder if this is more her issue. Any thoughts or areas I could do more research?


  6. Hi John,

    An interesting story!

    Pregnancy suppresses immune reactions to protect the baby from immune attacks. So the pregnancy experience would suggest that it is an immune reaction to a food toxin. Lactose intolerance is totally different, the undigested lactose feeds gut bacteria leading to bloating from fermented gases (if there is an immune response, it is to bacterial endotoxins, not the lactose).

    Much of the cream sold in stores is ultra-pasteurized (creating more folded casein that is hard to digest) and has additivies like carrageenan. See discussion starting here: See especially Perry’s comment and his link to Ray Peat’s article on carrageenan.

    That would explain why she reacts to heavy cream but not skim milk.

    So I agree with you: It’s not lactose, but either ultrapasteurized casein, carrageenan, or some other additive.

    You could test this by finding fresh cream that has no additives and/or has not been pasteurized.

    Best, Paul

  7. “You could test this by finding fresh cream that has no additives and/or has not been pasteurized.” [From your response just above.]

    How would one go about looking for cream like that?

    I’ve been surprised by your advocacy for cream given that, so far as I know, available cream comes from cows and milk that have had all the usual bad things done to them.

  8. Hi JBG,

    Well, giving up dairy is a plausible route. I like the taste too much to do that, so I try to find reasonably healthy dairy. Legal restrictions on the sale of fresh raw milk make that tougher.

    As far as where to get healthy cream, there are some reader thoughts on this thread: Also you can try

  9. My 15-year old daughter’s story connects wheat and lactose intolerance perfectly. After giving up gluten (mostly) last spring, she found she could tolerate a reasonable amount of dairy without Lactaid pills for the first time in her life. During last summer she went on a mission trip to Africa and was served peanut butter sandwiches every day. Her lactose intolerance and lots of other gut problems came back with a vengeance. When she got home last fall I encouraged her to go gluten-free. She did and after feeling better decided to be much more gluten-free than before. Not only is her digestion radically improved, she can have fairly substantial amounts of milk without any problems.

    I may suggest to her pediatrician that he test all lactose intolerant children for gluten intolerance. We’ll see how that suggestion goes over!

  10. Recently I’ve noticed awful side affects from cream and certain cheeses. Yesterday I had a cream of tomato soup followed by tart and cream. Afterwards I nearly died with stomach cramps. I have no problem with milk as I can drink glasses with my dinner. It’s only in the last year and I’m putting problem down to cream. Is their any supplement I can take or something to ease the pain?

  11. Daphne A Smithson

    Problems with cream but not milk, yoghurt or cheese.
    Also had issues with gluten, wheat, peanuts, chocolate and mushrooms.
    Quite a mixture!
    Any other ideas why this might be?

  12. Problems with cream but ok with milk, cheese, yogurt.
    Also problems with chocolate.
    Other food intolerances include wheat, gluten and histamine.
    Also shellfish, mainly prawns, mushroom and onion intolerance and peanuts.
    Any ideas?

  13. Hi Paul
    My friend ate some goats’ milk yogurt (very lightly pasteurized with no additives) for the first time. The second day after she ate the yogurt she experienced severe digestive discomfort,nausea,gas,eczema and acid reflux. They were not caused by anything else she ate. What should she do?
    Should she eat yogurt without lactose?Should she stop eating diary products? Do you know why she might have had this reaction?|

    Thank you


    • Hi Seth, I would assume the yogurt was contaminated with a pathogenic microbe – insufficient pasteurization may be the cause. Presumably this was a one-off food poisoning event. I see no reason why she should stop eating dairy products, unless it happens repeatedly. She might stick to pasteurized dairy. Best, Paul

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