Is gluten avoidance linked to a lower risk for depression?

I've talked a few times on this blog about how avoiding dietary gluten both within (see here) and outside of (see here) the context of coeliac (celiac) disease, the archetypal 'gluten is baddie' autoimmune condition, might have some pretty interesting effects on some aspects of a person's psychology. Today's post reflects yet more peer-reviewed science suggesting that there may indeed be something to see in this potentially important area; particularly pertinent to the presentation of depression or depressive symptoms.

So, the findings reported by Haley Zylberberg and colleagues [1] based on data from some 22,000 participants taking part in the US 2009-2014 National Health and Nutrition Examination Survey are the source material today. Some background material related to this cohort can be found here. They specifically looked at the "prevalence of depression, insomnia, quality-of-life variables, and psychotropic medication use in CD [coeliac disease] participants and PWAGs [people who avoid gluten] to controls." People who avoid gluten - PWAG - represent a group who don't have a diagnosis of CD but nonetheless similar to those who were diagnosed with CD, reported avoiding dietary gluten.

Results: "Depression was present in 8.2% of controls compared with 3.9% of participants with CD... and 2.9% of PWAGs." Even after adjustment for various confounding variables ("age, sex, race, income, and access to healthcare") those gluten avoiders (without CD) less frequently presented with depression compared with data from controls.

Added to the previous occasions where gluten consumption seems either to be linked to [some] depression or removal of gluten seems to positively impact on depressive symptoms at least for some, this is interesting work. Yes, quite a few more controlled trials are required to examine such relationships between food and mood. Although we can speculate on possible mechanisms [2] we don't really know why there may be an effect from gluten removal, but this is an emerging area of science; particularly in the context of how disruptive/disabling/damaging depression can be to someone.

Bearing in mind the caveats of this blog - no medical or clinical advice is given or intended - please don't assume that I'm advocating gluten removal for anything (unless clinically indicated) on the basis of this or other posts. If in doubt, consult your medical physician.

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[1] Zylberberg HM. et al. Depression and insomnia among individuals with celiac disease or on a gluten-free diet in the USA: results from a national survey. Eur J Gastroenterol Hepatol. 2017 Jun 27.

[2] Pruimboom L. & de Punder K. The opioid effects of gluten exorphins: asymptomatic celiac disease. J Health Popul Nutr. 2015 Nov 24;33:24.

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