Research presented at this week's American College of Gastroenterology meeting reported that the incidence of gluten sensitivity is far lower than the 6% to 7% of the population reported by many experts -- more in the range of 0.55%, or one in every 200 people. That's actually the lowest estimate for gluten sensitivity to date, and would make the cadre of gluten sensitivity sufferers only half as large as the group believed to suffer from celiac disease.
However, at least one top clinician in the field believes that the new study is flawed, and that many more people have gluten sensitivity than reported.
The dispute sets up a potential argument between the Columbia University Celiac Disease Center, where the study was performed, and the University of Maryland Center for Celiac Research, which performed earlier research on gluten sensitivity and whose director believes that up to 7% of people may have the condition.
The Columbia University study used data from the Centers for Disease Control and Prevention's Continuous National Health and Nutrition Study (NHANES). Participants in the study answered questions about whether they ever had been diagnosed with celiac disease, and the study also collected celiac blood test results.
If someone had been tested for celiac disease and was found not to have it, but still followed the gluten-free diet, then the Columbia University researchers labeled that person as gluten-sensitive for the purposes of their study. Out of 7,762 people, the study found 49 who fit that criteria, for a prevalence rate of 0.55%.
Slightly more women than men had the condition, according to the study. In addition, people with non-celiac gluten sensitivity tended to be older than the average NHANES participant (47 years old versus 40 years old) and had higher levels of so-called "good" HDL cholesterol, lower iron levels and lower body mass index.
The Columbia University researchers concluded that "the estimated prevalence of NCGS [non-celiac gluten sensitivity] in the U.S. is 0.55% which is approximately half that of celiac disease." They did say more studies are needed to fully understand the prevalence of the condition.
The research would seem to indicate that the gluten-free diet shouldn't be anywhere near as popular as it is, and that lots of people are eating gluten-free without cause. However, Dr. Alessio Fasano, director of the University of Maryland's celiac center and a top gluten sensitivity researcher, blasted the study, calling it "extremely biased" and "not informative."
Dr. Fasano told me that the study is based "simply on what patients report without an active process of diagnosis as outlined by current guidelines," which would lead the study authors to miss lots of gluten-sensitive people who don't yet realize they're gluten-sensitive (akin to how so many celiac disease sufferers remain undiagnosed).
"Furthermore, the current gluten-free market suggests that a much larger number of individuals embrace a gluten-free diet as compared to the numbers in the self-reported questionnaire," Dr. Fasano said. He added that any projected prevalence of gluten sensitivity will need to wait until a test for the condition has been developed.
If Dr. Fasano's 6% to 7% estimate is correct, around 20 million people in the U.S. alone could be gluten-sensitive. And his estimate isn't even the highest one out there -- read more in my article How Many People Have Gluten Sensitivity?
Honestly, I think the Columbia University study is flawed for a different reason: it only counts those who have been tested and found not to have celiac disease, but who went gluten-free anyway ... perhaps even against the advice of their physicians.
It doesn't count people who eat gluten-free because doing so cures their migraines, or eczema, or brain fog, or digestive symptoms, but who weren't tested for celiac disease. And it doesn't even try to count people who might find that the diet alleviates their symptoms, but who haven't gone gluten-free yet, possibly because no medical professional has suggested it.
For more on gluten sensitivity:
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