Wednesday, February 27, 2013


Tam sent this article about gluten intolerance, etc., on Slate.

As she pointed out, the fact that 1% of people can experience life-threatening damage from gluten is a big deal.

The article states that 30% of people in a clinical trial who thought they were gluten intolerant "felt better with gluten-free diets," but I think it's important to note that the researchers were not studying gluten intolerance but wheat intolerance.  (Wheat contains gluten, but it also contains other things to which people might be sensitive, so wheat intolerance is broader than gluten intolerance.)  After going on an elimination diet (eliminating wheat, cow's milk, eggs, tomatoes, and chocolate), participants were given capsules containing either wheat or a placebo (xylose) and reported their symptoms. 30% of patients reported being asymptomatic (less than 10 in a 100-point symptom scale) on the elimination diet but reported symptoms (more than 30 on the scale) when the wheat was reintroduced.

One thing I wonder about that is relevant to the elimination/reintroduction paradigm they used (i.e., "double-blind placebo-controlled challenge") is whether wheat (or gluten) sensitivity follows a dose-response pattern - in other words, do some people tolerate a small amount of wheat (like found in a capsule) just fine, but start to suffer as their intake of wheat increases?  It seems to me that I can handle a little bit of wheat OK but that my body is unhappy with larger quantities.  (I've never figured out quite where my personal cut off point is, and it's complicated by the fact that for me there appear to be interaction effects between wheat consumption and other stuff going on in my body, such that sometimes eating wheat doesn't seem to give me symptoms, but in combination with other factors, wheat makes me feel pretty bad.  Due to not knowing how much is too much, and that in many ways it is easier to eliminate than moderate my consumption, I have often gone off wheat completely to manage my symptoms.  Right now I'm off wheat, and other high lectin foods, entirely.)

Aha:  I accessed the supplemental information through my university library and it states:  "Wheat challenge was performed administering a daily dose of 13 g of flour, equal to about 20 g of bread."  If I am understanding this correctly, people in the "wheat" group were only eating the equivalent of 20 g of bread, which is less than 1 slice (I see numbers for slices of wheat bread like 28 g for a 69 calorie slice, 42.5 g for a 100 calorie slice).  

At that relatively low level of wheat consumption, I'm not sure that I would have shown a significant increase in negative symptoms from the elimination stage to the reintroduction stage in this study.  I could easily not have shown up in the 30% at the level of wheat used in the experiment, but I think I might meet the wheat intolerance criteria if the level of wheat were higher. 

I thought the comment at the end of the article, "patients convinced they have gluten intolerance might do well to accept that their self-diagnosis may be wrong," was kind of goofy and unclear.  What's the big deal with thinking you have gluten intolerance when you don't?  You might have some other disease that you should be treating instead, but I get the sense that this article's position is more that a lot of people are just delusional rather than truly ill.  Wheat/gluten is not some kind of nutritional superstar that will cause health problems for people who eliminate it from their diet because of an incorrect belief that they are intolerant to it. 


Tam said...

I was totally hoping you'd blog about this :-)

mom said...

I know someone who self-diagnosed gluten intolerance. Since there is no way to actually test for it, the only way to know is whether or not you feel better eliminating gluten/wheat. It doesn't matter if you are incorrect about being intolerant if you feel better and eliminate symptoms that make your life difficult.

Sally said...

Mom, right, a lot of people would be thrilled to find something that WORKS at all to alleviate their symptoms, regardless of what name doctors want to put on it.