For the 3 million people in America (myself included) with celiac disease — an autoimmune disorder triggered by the ingestion of gluten — culinary life is a series of intricate leaps, accommodations and back-steps. We peer at labels, know the difference between "gluten-free" and "certified-gluten free" and keep a dedicated set of dishes and pots at home to avoid contamination by flour dust, crumbs of bread, and bits of pasta indulged in by family members or roommates.
Even so, there are regular mishaps — like the gluten free Cheerios that weren't, or the news this past February that Chobani had recalled almost 85,000 cases of Flip Key Lime Crumble yogurt because they contained gluten, even though the containers were labeled gluten free.
But now, two worrying new studies suggest that accidental gluten exposure, even among celiacs following a gluten-free diet, may be far greater than we ever realized. A February study in the American Journal of Clinical Nutrition looked at gluten exposure detected by two new tests, one for urine and the other for stool. The tests detect peptides of gluten that make it through the digestive tract intact in all of us. (Nobody completely digests gluten, but most individuals don't have an adverse reaction to the undigested molecules).
Amounts of daily gluten in a regular diet can soar as high as 7,500 mg on average for women, and 10,000 mg on average for men. For celiacs, the recommended limit for safe consumption of gluten is a mere 10 mg a day — any more than that tiny amount can trigger symptoms and if exposure is ongoing, intestinal damage. That's because in celiac disease, gluten triggers an autoimmune response that damages the intestinal lining and impairs absorption of nutrients. The study, which examined data on individuals from two different clinical programs, found the average amount of gluten consumed on a gluten-free diet was 244 mg (by stool analysis) or 363 mg (by urine analysis).
"This study reflects what many celiacs experience in real life," explains analytical chemist Jennifer Sealey-Voyksner, one of the study's authors. "I was diagnosed with celiac in the early 2000s and even on a gluten-free diet, I was still getting sick. I began to actually analyze my own food using mass spectrometry techniques, and I found out that some of the gluten-free pastas I was eating, and even a body wash I was using, contained gluten."