Nocebo Effect May Cause Gluten Sensitivity [Video]

gluten sensitivity

People who claim themselves to be gluten sensitive or intolerant may not really have celiac disease. Instead, they may be experiencing a nocebo effect, which may be a cause for their gluten sensitivity perception. A recent study published in Nutrition in Clinical Practice examined who is more likely to diagnose themselves to have nonceliac gluten sensitivity (NCGS) even though they have no celiac disease. This population has gastrointestinal symptoms that improve after adopting a gluten-free diet. The results of the study show that among those who qualified in the study, those who self-diagnosed or were told to eat a gluten-free diet by an alternative health practitioner, general practitioner, or a dietitian are more likely to report to have NCGS.

The cause of NCGS remains somewhat of a mystery in current research. However, a small yet rigorous study that was published last year in Gastroenterology by Jessica Biesiekierski, Ph.D., and her colleagues showed that eight percent of the NCGS participants who ate any amount of gluten showed any significant gluten-specific effects. In the double-blind crossover study, 37 subjects with irritable bowel syndrome and self-diagnosed NCGS were randomly assigned to a two-week diet of FODMAPs, or reduced short-chained carbohydrates. Then they were put in a week-long low-gluten or high-gluten diet or a whey protein diet which served as a control group. At the end of the study, researchers found “no diet-specific changes” in the biomarkers in their blood serum or feces that indicate auto-immune activation, fatigue, or inflammation other than in the eight percent. Thus, Biesiekierski and her colleagues found no evidence that gluten-free diets have any “specific or dose-dependent effects” on those with NCGS with diets low in FODMAPs.

A recent review published in a Spanish-language journal Gastroenterlogía y Hepatología stated that patients with NCGS may have “overlooked minor CD [celiac disease] and diarrhea-predominant irritable bowel syndrome” based on recent studies. Researchers postulated that the real culprit behind NCGS may be from FODMAPs from wheat rather than gluten itself. Since there is no current evidence that eating gluten causes gluten sensitivity, the nocebo effect may be the best hypothesis to explain this phenomenon.

Although the nocebo effect is lesser known than its positive counterpart, the placebo effect, the former has been known to cause illness and other manners of pain and discomfort due to negative suggestions and expectations. For example, physicians and nurses could sometimes unintentionally give negative outcomes and suggestions about a patient’s condition and treatment, which can cause a patient’s health to spiral even further down. According to a German-language review in Deutsches Aerzteblatt International, the nocebo effect is learned by “Pavlovian conditioning and reaction to induced expectations.” Therefore, the words that clinicians use can negatively (or positively) affect patients’ outcome.

As in the case of gluten sensitivity, the nocebo effect can cause some people to believe certain things or treatments can harm them or make them feel worse. Although there is a lack of sufficient research and data about the cause and effect of the nocebo effect, perhaps taking a closer look at the better-researched placebo effect would yield some answers to why people believe certain treatments are better or worse.

By Nick Ng


Deutsches Aerzteblatt International
Real Clear Science Gastroenterology
American Gastroenterology Association
Nutrition in Clinical Practice
Gastroenterlogía y Hepatología

4 Responses to "Nocebo Effect May Cause Gluten Sensitivity [Video]"

  1. Tabitha Farrar   August 7, 2014 at 6:45 am

    This is an excellent article, the brain is so powerful!

    I have linked to it on the health daily digest today, thank you for researching this so well, and I will certainly refer to the resources that you have in the all to regular dinner-table arguments that I have with Boulderites who claim gluten intolerance for no reason whatsoever. Maybe if we can make it unfashionable the fad will disappear and I can go back to serving bread without feeling as if I am doing something taboo!

    • Nick Ng   August 7, 2014 at 11:26 am

      It would be challenging since the gluten-free business is a multi-billion dollar business. Plus like any diet, fitness product or guru, some people have a tendency to get emotionally attached to it if they like it and perceive it as helpful, hence the placebo effect.

      • Tabitha Farrar   August 9, 2014 at 6:08 am

        People certainly get attached to a label. I was vegan some years back for about 5 months before I noticed that my body was not faring will without meat and dairy. The only hard part about returning to a normal diet was the mental aspect of giving up the label. Luckily for me, as soon as I was able to identify that as the problem I was able to happily let my ego go 🙂

  2. Michael Schultheiss   August 6, 2014 at 4:50 pm

    It is absolutely mind-blowing to think that such phenomena could originate in the brain. Excellent article, Nick!


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