For me, a recent study (AD Sabatino et al. Clin Gastroenterol Hepatol 2015; 13: 1604-12, editorial 1613-15) was particularly interesting. While it had “positive results,” these findings were based almost entirely on the results of three patients.
In brief, this study examined 61 adults (w/o celiac disease) who believed that gluten induced intestinal and extraintestinal symptoms. These individuals were randomized to receive either 4.375 g/day of gluten or rice starch via capsules. This amount of gluten is equivalent to 1 sandwich or 2 slices of bread.
- Overall, intake of gluten significantly increased symptoms compared to placebo (P=.034), including bloating, pain, foggy mind, depression, and aphthous stomatitis.
- Looking at a scatterplot (Figure 4), it is abundantly clear that all of these findings are driven by 3 patients.
- “In the vast majority of patients the clinical weight of gluten-dependent symptoms was irrelevant in light of the comparable degree of symptoms experienced with placebo”
- “Our study did not provide any progress in identifying possible biomarkers of NCGS [non-celiac gluten sensitivity]”
This type of study, with mixed conclusions, led the editorialists to quote Spock (from Star Trek):
“In critical moments, men sometimes see exactly what they wish to see.”
Then, the editorial provides a historical context of NCGS with a review of the relevant prior studies. Other comments:
- “These findings can be a Rorschach test of sorts, in which the viewer draws interpretations that are based on his or her prior beliefs about NCGS.”
- The authors note that both the gluten and the control arm likely had a significant nocebo effect (negative placebo effect),
- “This trial, like its predecessors, seems only to contribute to the uncertainty about NCGS.”
Related blog posts:
- Wheat Intolerance Syndrome? | gutsandgrowth
- “Gluten-Related Disorders” (Part 2) | gutsandgrowth
- An Unexpected Twist for “Gluten Sensitivity” | gutsandgrowth