What's the difference between wheat allergy, gluten allergy, and celiac disease?

There is confusion among many people surrounding the question of celiac disease, wheat and/or gluten allergy. Perhaps I can help shed some light.


First, Celiac disease is an autoimmune reaction that is triggered by exposure to gluten. What this means is that when your body sees gluten, it starts attacking itself - primarily in the small intestine, but also in other parts of the body. Symptoms can include bloating, chronic diarrhea, irritable bowel syndrome, constipation, skin rash, and other disease states such as anemia, hypothyroidism, and osteoporosis. Diagnosis can be tricky as there is no one perfect diagnostic test. There are a couple blood tests that are pretty good provided you've been eating gluten regularly for the couple weeks preceding the test. The other test is via a biopsy, where they actually go in to the small intestine and take a tissue sample. This is considered to be the "gold standard" among many clinicians, however it's still not 100%. A third option (and one gaining some momentum in the evidence circles) is to use a genetic test to aid in diagnosis. There are a couple genes that when present can give you an estimate of your lifetime risk of developing celiac disease (the DQ2 and DQ8 alleles). One of the benefits of this test is that if you DON'T have the genetics, you don't have celiac disease.


Second, food allergies and sensitivities (in this case wheat or gluten) can lead nebulous discussion on semantics. One type of allergy is the classic "eat a peanut and your throat swells closed and you die" type reaction. Those are well defined and understood. As for the rest, let's just call them "having an undesirable reaction to a food". These are less well understood, but still problematic for many people. For more info, see my previous post entitled "Are blood tests for food allergies a waste of time".


So given these two scenarios, what now? Barring laboratory diagnosis, a clinically useful option is to eliminate gluten (anything containing wheat, rye, barley, or oats) completely from the diet and to watch for symptomatic improvement. There is debate on how long one should abstain - anywhere from a few days to 6 months, but that should be tailored to the patient by the clinician depending on a number of factors. If there is an improvement in symptoms, that's your first clue. If not, it's not likely the culprit. If you notice an improvement, the next step is to challenge the food you suspect.


To distinguish between wheat and gluten as a problem, you can start by challenging rye or barley. These both contain gluten, but are not wheat - hence if you note a reaction, it's from the gluten. If that's ok, then challenge wheat. If that is a problem you have your answer. When challenging foods it's best to use that particular food in it's purest form ex/ cream of wheat (for wheat), or straight barley. This helpful because in bread for example, there are a number of other ingredients you may be reacting to. These types of diagnostic experiments are best done with the help of a health provider you trust, to ensure they're being done properly.


Since the treatments for allergies and intolerances are the same (avoidance of your problem food), does it really matter what one calls the problem?  In my opinion it does,  as accurate diagnoses are the hallmark of good medical care and decision making.  Food "allergies" and celiac disease have significant differences in long term health outcomes, so knowing what one is up against is an important step.


Speak soon,


B