Gluten and diabetes: The headlines get it wrong again
Another study was released recently that purports to “prove” that gluten-free diets are associated with increased risk for type 2 diabetes. As with many studies of this type, the findings were misinterpreted but fed into the media’s continual need for titillating headlines. I thought this hubbub would pass by now, but reports about this study (such as this piece of tripe from The Washington Post) seem to be gaining more traction than usual, fueling the misunderstanding and misinformation that plagues nutritional thinking. While I thought this would just pass, it looks like it will not and I’m therefore posting my comments.
First, a few words about epidemiological studies of the sort this group used, the Physicians’ Health Study population of health professionals. The participants were asked diet questions, then health status was tracked over several years. Putting aside the imprecision of such dietary recall questionnaires, we know that such studies simply cannot—no matter how large the study, no matter how meticulous the questions—establish cause-effect relationships; they can only suggest a potential association. The purported 13% difference in type 2 diabetes incidence is minor, given the dramatic imprecision of epidemiological studies; confident associations are typically much larger than this: 40% or 50%, for instance. This does not stop, of course, media people, who are journalists at best, paid marketing people for the grain industry at worst, to propagate their misinterpretations.
To further illustrate the problems inherent in epidemiological studies, Continue reading