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Food antigen-induced immune responses in Crohn’s disease patients and experimental colitis


Well-known member
One of the few studies that did a wide antibodies presence study on common foods in patients with Crohn's disease.

It shows a very high IgG response against buckwheat, corn, oat, pecan, cabbage, lettuce, celery, rice, onion, spinach, tomatoes, grapefruits and yeasts.

The antibody response is strongest against grains, vegetables and several fruits. It could partly explain the effectiveness of low fiber EN.

In comparison, there is no major response against protein dense meat and fish, which lack fermentable fiber and are absorbed higher up the GI tract.

This also coincides with the recent study that shows unfermented fructans drives an inflammatory immune response in people with crohn's disease. https://www.gastrojournal.org/article/S0016-5085(22)01150-7/fulltext

In 2016 another study showed a fructan challenge causes abdominal pain in crohn's disease patients.

We also know that there is an unexplained immune response to saccharomyces cerevisiae in about half of patients with crohn's disease. The so called ASCA test relies on this immune response as a diagnostic marker. Basically a direct or cross response to baker's yeast.

The immune response to food antigen is much higher in CD than in UC, but this had already been established.

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The big thing I see here is that Crohn's patients are having immune responses to *many* foods. This could mean two things:

1. Crohn's patients' immune systems are *responding* much more to everything, and/or

2. Crohn's patients' immune systems are *exposed* much more to everything

#1 doesn't really fit with other information we have about Crohn's, because Crohn's is fundamentally a gut-based phenomenon. The Crohn's immune system seems pretty normal in other ways.

#2 makes sense because we can see the damage in the intestines, and we can assume that a damaged gut barrier layer will allow all sorts of antigens in--thus exposing the Crohn's immune system to various food antigens that healthy people aren't exposed to.

Fix the damage, repair the gut barrier, and the immune response should stop.


Well-known member
Right, a common counterargument to these food antigen studies has always been that food-specific IgG are somehow natural and would be more frequent in people with crohn's disease who have increased permeability due to inflammation. It is another chicken-or-egg argument.

But the fact the immune response against a fructan challenge is quite severe, even in people with CD in remission, makes me question if these immune responses against food antigen are just a secondary event.

The fact EN lacking in fiber causes such rapid remission is of interest too.

The recent study on unfermented b-fructan fibers is interesting too.

Notice also that with a damaged gut and an immune response to many foods, it shouldn't be a surprise that it would result in inflammation, which might prevent the gut barrier from healing. So EEN can help by reducing the antigen content of food, including the bacterial content, resulting in lower inflammation and perhaps a chance to heal.
In my son's experience, Pediasure with fiber was equally as effective as Pediasure without fiber, and both were not quite as effective as Pediasure Peptide.
Is there any reason why sole, being a fish, causes so strong antibody response whereas wheat is so low?. This is very puzzling to me.


Well-known member
All you can really make out of these tests is that people with crohn's disease have more circulating antibodies against certain food groups.

You can't really draw any conclusions from individual foods. Antibodies are notoriously problematic. We have known for decades that people with crohn's disease have IgG against saccharomyces cerevisiae, known as baker's yeast. In fact it is specific enough that the ASCA test which tests for these circulating antibodies, is helpful for diagnostic purposes.

Yet, no one is recommending to stop eating baking products. Because we don't know if these antibodies are antibody titres caused by active ingestion of baking products containing s. cerevisiae, or if they are just immunological memory, we don't know if they are part of an immune response at the level of the intestine, and they might just be cross reactivity.

But, it is still very interesting to see a low antibody response to food groups like fish and meat, and a much higher response to vegetables, grains and fruits.

The old wisdom regarding crohn's disease has always been to eat low residue and to employ EN during actives phases of disease. Regardless of the chicken or egg question, during phases of disease, it seems wise to go for nutrients that are absorbed as proximally as possible.
This is a very curious study. I will soon do an IgG allergy test myself, and share results here in case anyone is interested. I seem to react severely to specific foods, my histamine is sometimes sky high, and my cationic eosinophil protein is also significantly elevated - but all my IgE specific tests were negative. At the same time my ileal Crohn's seems to react very significantly to diet, while polymeric EEN completely failed for me. And while I understand its practically impossible to draw conclusion from specific antigen reactivity, the part that is most confusing for me in this study is, polymeric EEN-s almost always contain corn or derivatives or corn, that according to this study has the highest IgG reactivity, and still tend to work rather well for a lot of people. And Crohnies are notoriously bad at being able to tolerate even lactose free dairy, and the level of allergies for those seemed rather low.

In my case, once I switched to SCD / IBD-AID, my symptoms almost disappeared, while that was the time when I actually increased my fiber intake a lot mostly through zucchini, carrots, almonds, and oats very recently. That was around the same time when I started taking probiotics. So to me, the theories around gut microbiome reactivity seem much more appealing and comprehensive vs our bodies reacting directly to food. Because in that theory, it can be reasonably explained why a low / no fiber approach could work for some (EEN) while for others, a higher fiber / fructan, less sugar, less artificial, whole-food based approach (CDED, SCD, IBD-AID, etc): in the first case we starve out the potentially harmful unidentified bacteria, in the second, we support the good bacteria more than we support the bad ones and let them create a new homeostasis. And then there is the CDED + PEN which seems to combine this 2 disciplines with quite impressive results. For now I look at this study more as the mere consequence of an injured epithelial barrier and long-term memory of immune cells - as far as I have read, most medical organisations dealing with allergies and immune mediated diseases seem to agree that no reliable conclusions can be derived from IgG positivity to specific antigens.

I am also going to try elemental EEN very soon, which should give me a better clue if it was the intact milk proteins causing me those horrible cramps while on them..