Eating Gluten Does Not Seem to Impair Cognitive Function Among Non-Celiac Women

Celiac.com 05/31/2021 - For people without celiac disease, does eating gluten have an impact on brain health, specifically on cognitive function? A recent study of nearly 14,000 non-celiac women at midlife revealed no statistical evidence of any association of long- or short-term gluten intake with cognitive function.

More and more people are eating gluten-free for perceived health benefits that may not be real. It's true that cognitive impairment, sometimes called "brain fog," is a common symptom reported by many people before they are diagnosed with celiac disease. In those cases a gluten-free diet generally results in improvement of the symptoms. However, data are lacking in individuals without celiac disease. A recent study set out to "examine whether gluten intake is associated with cognitive function in women without celiac disease." 

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Their study included US women who participated in the longitudinal, population-based Nurses’ Health Study II and had not previously or subsequently been diagnosed with celiac disease. Subjects answered a questionnaire that was used to cumulatively average gluten intake cycles prior to cognitive assessment. They then took a battery of tests on psychomotor speed and attention score, learning and working memory score, and global cognition score. They research team found no connection between long-term gluten intake and cognitive scores in middle-aged women without celiac disease. 

Their results, "do not support recommendations to restrict dietary gluten to maintain cognitive function in the absence of celiac disease or established gluten sensitivity." But how useful was the study? What did they actually measure? What did they actually show us? The study actually reveals very little, if anything.

Celiac.com does not recommend a gluten-free diet for people who do not have celiac disease or gluten sensitivity, but we also do not oppose it. A properly structured gluten-free diet can be every bit as nutritious and health-promoting as a diet that contains gluten. 

However, we also do not agree with studies with conclusions that seem to be designed to scare people off of a gluten-free diet, or to soft-pedal a diet that contains wheat. The study does not say that there is no cognitive benefit to giving up gluten for people who do not have celiac disease or gluten intolerance, or that those without celiac disease might also benefit from a gluten-free diet.

The benefits or harm of a gluten-free diet in people who are not gluten-free remains poorly studied. Even in people with celiac disease, the implications of a long-term gluten-free diet have not been well-studied, and plenty of studies make unproven nutritional assumptions about those implications based on scant data.

We believe that each person must choose their diet for themselves, and that many folks without celiac disease may choose to eat gluten-free for reasons that make sense to them. Some may do so because they perceive themselves to think more clearly when they do not eat wheat. 

The problem, from our perspective is that the study basically says: We looked at a bunch of women who eat wheat and gluten in various quantities. Their brains seem fine. Nothing to see here.

People concerned about a potential connection between brain function and wheat consumption deserve more than a study that says, in effect, "hey, plenty of women eat gluten, and whether they eat a lot or a little, their brain test results seem fine." Telling us that eating wheat does not seem to cause brain impairment in non-celiacs is helpful. It is. But it's only part of the picture.

As far as we can see, none of these subjects had brain function tests when eating gluten compared with tests when they were gluten-free. Nor did the test compare women who ate wheat to similar women on a gluten-free diet (but really, what was needed here was the former, a comparison of the same group of people, perhaps tested when eating different gluten levels, then re-tested after a prolonged gluten-free diet). 

For all of the seemingly grand implications of the study, it really doesn't tell us much about brain function in people who eat gluten. It doesn't tell us if there are any benefits brain wise to giving up gluten. Look, it could be that giving up gluten has a negative impact on non-celiacs, but that remains unproven.

We really need a more comprehensive and focused study to help tell us what, if any, impact gluten has on the cognitive function of non-celiacs, along with what benefits, if any, they might have when giving up gluten.

Read more in JAMA Netw Open. 2021;4(5):e2113020

The research team included Yiqing Wang, PhD; Benjamin Lebwohl, MD, MS; Raaj Mehta, MD; et al Yin Cao, ScD, MPH; Peter H. R. Green, MD; Francine Grodstein, ScD; Manol Jovani, MD; Paul Lochhead, MBChB, PhD; Olivia I. Okereke, MD, MS; Laura Sampson, MS, RD; Walter C. Willett, MD, DrPH; Qi Sun, MD, ScD, MMS; Andrew T. Chan, MD, MPH. They are variously affiliated with the Clinical and Translational Epidemiology Unit, Massachusetts General Hospital, Harvard Medical School, Boston; the Division of Gastroenterology, Massachusetts General Hospital, Harvard Medical School, Boston; the Celiac Disease Center, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York; the Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, New York; the Division of Public Health Sciences, Department of Surgery, Washington University in St Louis, St Louis, Missouri; the Division of Gastroenterology, Department of Medicine, Washington University in St Louis, St Louis, Missouri; the Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, Illinois; the Department of Internal Medicine, Rush Medical College, Chicago, Illinois; the Division of Gastroenterology and Hepatology, Johns Hopkins Hospital, Baltimore, Maryland; the Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts; the Department of Psychiatry, Massachusetts General Hospital and Harvard Medical School, Boston; the Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts; and the Department of Nutrition, Harvard T. H. Chan School of Public Health, Boston, Massachusetts.