Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
5 Sep

How Common is Gluten Sensitivity?

wheatI’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. My own story was that of a lifetime grain-eater who defended my “right” to eat grains until I was 47 – until the evidence was just too overwhelming to ignore. Once I gave them up as part of a 30-day experiment, lo and behold, my arthritis cleared up, my lifelong IBS went away, and my occasional GERD disappeared. Ditching grains, especially wheat, changed my life for forever and made me understand how easy it is for so many people to overlook this possible problem. 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:

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:

  • Diarrhea
  • Bloating
  • Abdominal pain
  • Eczema
  • Headache
  • Foggy brain
  • Fatigue
  • Depression
  • 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.

One study found that around 12% of healthy people’s blood samples tested positive for antibodies to IgG. Fecal tests, however, indicate that around 29% of healthy people test positive. If the fecal antibody tests are accurate and reflective of gluten sensitivity, that’s nearly a third of Americans!

There’s also a genetic component to gluten sensitivity and celiac, the HLA-DQ gene. According to some reports, almost every permutation of the HLA-DQ gene is associated with some manner of gluten sensitivity, particularly the haplotypes HLA-DQ2 and HLA-DQ8. Only HLA-DQ4 has never been linked to any form of gluten sensitivity, and less than 1% of the American population possesses a homozygous HLA-DQ4/4. If that holds true, then the vast majority of Americans have the genetic potential toward gluten sensitivity.

Of course, when you consider that everyone – regardless of genetic proclivity toward autoimmunity – releases zonulin, the regulator of intestinal permeability, when our intestinal lining is exposed to gliadin (a component of gluten), a universal response to gluten looks likelier. Sure, we all know plenty of people who can eat a sandwich without complaining, or that guy who claims he could never live without wheat. Gluten and related fragments may be getting through the intestinal lining in these people, but their immune systems mop them up pretty handily before they can do much damage. But what happens if their immune system is impaired, maybe because of a period of chronic stress or overtraining? What happens if their microbiomes are ravaged by antibiotics and poor diet and thereby absent the bacterial species necessary to fully degrade gluten? There’s no clinical trial tracking the effects of usually healthy people undergoing chronic stress or antibiotics on their sensitivity to gluten, but people are stressed, people are overworked, and their guts are messed up. It’s hurting our health in many different ways, and I wouldn’t be surprised if there is a lot more undiagnosed gluten sensitivity out there because of it.

It’s conceivable that gluten could be doing damage and causing constant, low-grade inflammation without you even knowing it. This is why folks who go Primal and give up wheat and other gluten-containing grains become more “sensitive” to wheat upon reintroduction. It’s not that going Primal has suddenly made them intolerant of gluten; it’s likelier that going Primal has made them more sensitive to their gluten sensitivity. It was probably always there, but they never knew what they were feeling until they removed it and then tried to reintroduce it.

As for figuring out if you’re gluten sensitive, I suppose you could go for one of the stool or blood tests provided by EnteroLab or Cyrex Labs (although not everyone is enamored with EnteroLab). But honestly? The gold standard is to just not eat gluten for a few weeks to a month and then reintroduce it and see how you feel. If any strange symptoms pop up (see list above), you’re probably sensitive to gluten. If you want further clarification at this point, then go for the tests. Just try the diet first. It’s gonna be your best (and probably the only necessary) lens.

We don’t have any real solid answers, sadly, just hints. But isn’t that how questions of human physiology tend to play out? It might be 12%, or maybe 30%, or perhaps even a higher (or lower) percentage of the population. Whatever the number, I know that grains don’t serve me well, and they probably aren’t doing you any favors either. So try giving them up for 30 days and seeing how you feel. After all, you aren’t missing out on anything nutritionally by avoiding gluten, except for some potential nasty health issues down the line.

That’s what I’ve got, folks. What do you think? Are you gluten sensitive? Let me know in the comments, and thanks for reading!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

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