Recently by Mark Sisson: The Low Carb Flu
I’ve long suspected that everyone has some degree of sensitivity to gluten, even if they’ve never been formally diagnosed and even if they don’t notice any overt symptoms after eating it. Now we have concrete evidence that non-celiac gluten sensitivity actually exists. A recent study, which I highlighted in Weekend Link Love, confirmed the existence of non-celiac wheat sensitivity. Subjects without the atrophied villi (tiny projects that line the intestines and help absorb nutrients) characteristic of celiac and without positive tests for various markers that indicate celiac experienced gluten-related symptoms after a blinded wheat challenge. It doesn’t give us much of a clue as to the prevalence of sensitivity, but it establishes that such a thing might exist among the general population.
It’s not even the only study. It’s just the latest of many to establish and/or hint that non-celiac gluten sensitivity exists:
- “Spectrum of gluten-related disorders: consensus on new nomenclature and classification.” (2012)
- “Gluten causes gastrointestinal symptoms in subjects without celiac disease: a double-blind randomized placebo-controlled trial.” (2011)
- “Is gliadin really safe for non-coeliac individuals? Production of interleukin 15 in biopsy culture from non-coeliac individuals challenged with gliadin peptides.” (2007)
But how prevalent is it? We know that celiac disease is on the rise; what about gluten sensitivity?
First, before we get into numbers, let’s go over the difference between celiac and gluten sensitivity:
Celiacs have persistent and profound perforation of the intestinal lining (at least as long as they’re eating gluten) as well as atrophy of the villi, thereby allowing foreign proteins — including, but not limited to, gluten — constant access into the bloodstream and impairing nutrient absorption. Folks with “mere” gluten sensitivity have transient and milder intestinal permeability, or sometimes none at all.
Celiac is an autoimmune disease that inspires the immune system to attack the body’s own tissues, while in gluten sensitivity, the immune attacks are directed solely against components of the diet (gliadin).
Celiac disease seems to involve the “adaptive immune system,” while gluten sensitivity involves activation of the “innate immune system.”
In celiac, the inflammatory cytokine IL-17 is elevated. In gluten sensitivity, it is not.
So gluten sensitivity and celiac disease are two distinct “clinical entities” with the same environmental trigger — gluten — and many of the same symptoms:
- Abdominal pain
- Foggy brain
- Joint pain
- Numbness in the extremities
And sometimes the symptoms aren’t obviously connected to gluten (or anything you did or ate). It’s tough to ignore persistent diarrhea that precipitates (pun intended) upon gluten ingestion. That’s an obvious symptom that may clue you in, especially if you’re aware of the potential problems with gluten, you’ve just eaten something containing it, and you’re pondering all this while filling the toilet. But gastrointestinal symptoms don’t always present themselves in gluten sensitivity, as in this study, where 13% of subjects with gluten ataxia (a kind of neuropathy) had no GI symptoms. I mean, who hasn’t felt brain fog from time to time, or been tired in the middle of the day, or had some itchy rashy red skin, or had sore joints before? Most people would never think to link these to the bagel they just ate (ok; you guys might).
Testing for gluten sensitivity is tough because there’s no real standard yet. You’ll notice that the recent study didn’t determine gluten sensitivity solely by running patients’ labs and looking for a certain figure; they had to painstakingly and laboriously eliminate confounding variables (like celiac) through extensive lab testing, and then run a double blind wheat challenge to see if symptoms still arose. That grand, single overarching lab test doesn’t exist, not yet anyway.
Well, that’s not exactly true. There are tests that measure the presence of anti-gliadin IgA (a gliadin antibody) in the blood and in the stool. Antibodies in the blood mean that gliadin made it through the intestinal lining into the blood, where the body mounted a defense against it; antibodies in the stool indicate the presence of antibodies in the gut, where the body has mounted a defense. Gut antibodies, however, come before blood antibodies. For that reason, fecal antibody tests are regarded as more accurate for testing gluten sensitivity, because blood antibodies only show up after significant intestinal damage has allowed gliadin to pass through. You could test positive for fecal antibodies and negative for blood antibodies if your intestinal lining remained fairly intact.