Gluten is the protein found in wheat, barley and rye, and it is what gives many foods their form and texture. Think of it as the "glue" that holds bread products together. Gluten enteropathy, or Celiac Disease (CD), is an autoimmune disease in which the individual reacts to gluten and produce an autoimmune-mediated attack on their intestines. Currently it is estimated that CD affects 1 in every 133 people in the US, with a predilection for Caucasian people and women. It is estimated that 80% of people with Celiac Disease are unaware they have the disease . Diagnosis of CD requires either a positive Anti-gliadin antibody test or Tissue Transglutaminase test, as well as a biopsy of the small intestines showing gross damage to the villi of the intestines. Often times a third test is used, a genetic test that looks for the "Celiac genotype" of either HLA-DQ2 or HLA-DQ8.
Okay, so it makes sense that if you have CD you shouldn't eat gluten. But then there's the real weirdos out there: the 1.6 million Americans who are on a gluten free diet but are not diagnosed with Celiac Disease.
Why in the world would people without Celiac Disease go gluten-free?..
Because you don't have to be Celiac to have an immunological, and very real reaction to gluten.
As a matter of fact, scientists now believe that occult cases of CD account for an astonishingly low number of gluten sensitive individuals. As a matter of fact, research is now showing that those people with enteropathy (disease of the intestinal tract) represents only 1/3 of the patients with neurological manifestations of gluten sensitivity . The vast majority of autoimmune patients are highly sensitive to gluten (as well as other food proteins) and feel much better when they remove it from their diets. Remember, just because the intestinal tract itself isn't being attacked doesn't mean that the immune system isn't attacking another tissue. In Celiac Disease it's the gut that gets chewed up; in Rheumatoid Arthritis it's the joints; in Hashimoto's it's the thyroid. In any case the immune system reacts to the foreign protein and stimulates an immune attack- it's just a matter of where they send the troops.
The problem is that most doctors have yet to acknowledge that non-celiacs can have a problem with gluten. To them, the Celiac test IS "the gluten test", but that is absolutely not true. I have heard countless stories from patients with the same experience: "my doctor said it was all in my head... They said I had no problem with gluten." It's so sad, because these people knew that their bodies did not tolerate gluten, but at the insistence of their ignorant doctors they continued to eat the foods that were contributing to their misery.
There are three main problems with traditional Celiac testing that cause gluten-sensitive folks to fall through the cracks.
1. The majority of testing uses the antibody IgA. However secretory IgA is commonly depleted in autoimmune patients, who make up a large percentage of gluten sensitive people. This means that the IgA test can come back low enough to fall into the "negative" range, when in actuality the patients' body was just not making any IgA, let alone IgA against gluten. To combat the risk of false negatives, look for tests that include either IgG or IgM in addition to IgA.
2. Celiac genotype testing is boarder-line useless, but many physicians will not consider you to have CD unless you have the HLA genotype. While 90+% of CD patients are HLA-DQ2 positive, approximately 30% of those of Caucasian decent have this genotype, too! This means that the genotype testing has pretty good sensitivity, but really lousy specificity. That and again, this test is looking for people with occult Celiac Disease, so those who are non-celiac gluten-sensitive would be passed by yet again.
3. The main problem with celiac and gluten testing is that the test only looks for sensitivity against one of the many components of wheat (see below ). The anti-gliadin antibody testing used do diagnose CD only tests for Alpha Gliadin- one of 12 or so components of wheat and gluten! Not only that, but most current testing does not test for reactions to wheat versus rye or barley- they assume that the structure is similar enough that they would all produce a positive test result to Alpha-Gliadin.
The cheapest way to find out if you have a food sensitivity is to do a good ol' fashioned food elimination test, although even this "gold standard" is not perfect in my opinion. The premise is simple enough- cut questionable foods out of your diet for a few months, then add it back in and see what happens. We need to re-learn how to listen to our bodies as a species. Back when we were in the bush we would simply know to avoid a food if it made us feel bad. Nobody needed blood tests and peer-reviewed, double blind, placebo controlled trials- it was common sense that your body knew what's best.
I recommend doing an elimination diet with the most common allergens: gluten, dairy, soy, eggs, corn and peanuts. Give your gut and your immune system a break from these inflammatory foods for a few months with absolutely no cheating. If you can do things to heal your gut (coming in a later post) during that time then all the better. After a few months have passed, slowly start re-introducing foods into your diet, about once every 3-4 days. Recall, it takes the epithelial cells in your gut approximately 3-5 days to regenerate, so it will take you that long to rebound from each new food. As you reintroduce foods, keep an eye out for any symptom: from restless leg syndrome, to gut problems, to pain or insomnia. Remember, the immune system lives in the entire body, so symptoms can pop up anywhere. If you have an autoimmune disease, specifically keep your eyes peeled for symptoms of your disease (ex. joint pain in RA, hypo or hyperthyroidism symptoms in hashimoto's or graves disease, etc). Of course, the entire point of the diet is to avoid the foods that produced any adverse reactions, so listen to your body and stay away from the stuff after that!
For those of you who like to see results that clearly tell you "you can eat this, you can't eat that", you are in luck. Cyrex labs offers phenomenal and, in my opinion, invaluable tests that will surely steer you in the right direction.
 Chart recreated from Datis Kharrazian's seminar notes "Understanding the complexity of gluten sensitivity" 2011
 J neurol Neurosurg Psychiatry, 2007:72;560-563. Gluten sensitivity as a neurological illness.
[Tom O'Bryan] http://www.youtube.com/watch?v=DjvKrAvolMQ
[THE lab] http://www.cyrexlabs.com/
[Great GFDF recipes!] http://www.nourishingmeals.com/
[An example of how gluten attacks more than the gut] http://www.livingwithout.com/issues/4_12/ataxia-2366-1.html