Der Nocebo-Effekt, nicht Gluten, kann bei vielen IBS-Patienten Symptome auslösen. Die Studie ergab keinen signifikanten Unterschied in Bezug auf das Aufflammen der Symptome, wenn diese Patienten Riegel mit Weizen, gereinigtem Gluten oder einer glutenfreien Scheinsubstanz konsumierten.

I’ve linked to the news release in the post above. In this comment, for those interested, here’s the link to the peer reviewed journal article:

https://www.thelancet.com/journals/langas/article/PIIS2468-1253(25)00090-1/abstract

From the linked article:

**The nocebo effect, not gluten, may trigger symptoms for many with IBS**

A new study suggests that for many patients with irritable bowel syndrome who believe wheat or gluten trigger their symptoms, the expectation of a food causing discomfort may play a larger role than the food itself. Research published in The Lancet Gastroenterology & Hepatology **found no significant difference in symptom flare-ups when these patients consumed bars containing wheat, purified gluten, or a gluten-free sham substance**.

This mind-body connection can work in two opposing ways. When a person’s positive belief in a treatment leads to genuine symptom improvement, even if the treatment is inactive, it is known as the placebo response. Conversely, when a person’s negative belief or fear about a substance causes them to experience adverse effects from it, even if the substance is harmless, it is called the nocebo response.

The study’s main finding was that there were no statistically significant differences in symptom worsening among the three challenges. After the wheat challenge, 39 percent of participants experienced a significant worsening of symptoms. Following the gluten challenge, 36 percent reported a symptom flare-up.

After the sham challenge, which contained neither wheat nor gluten, 29 percent of participants still experienced a significant worsening of symptoms. The small differences between these groups were not large enough to be considered statistically meaningful, suggesting that wheat and gluten were not the specific triggers for the majority of these individuals.

Adverse events were common, but they occurred at nearly identical rates across all three conditions. An overwhelming 93 percent of participants reported adverse events like bloating, abdominal pain, or changes in bowel habits after each of the wheat, gluten, and sham challenges. The fact that negative symptoms were reported just as frequently after consuming the inactive sham bar points toward a powerful nocebo effect, where the anticipation of symptoms appeared to generate them.

A secondary and revealing component of the study involved objectively measuring adherence to the diet protocol. Participants were asked to provide stool samples, which were tested for gluten immunogenic peptides, a reliable marker of recent gluten consumption. While participants self-reported high levels of compliance, with 97 percent of the challenge bars reportedly consumed, the objective stool tests told a different story.

The results showed that 57 percent of patients had detectable gluten in their stool at times when they should have been on a strict gluten-free diet, such as before a challenge week or during the sham week. Conversely, 25 percent of patients had no detectable gluten after the wheat or gluten challenges, suggesting they did not consume all the challenge bars. Ultimately, the objective data indicated that only about one-third of the participants were fully compliant with the study protocol.

The researchers also conducted a follow-up to assess how learning their personal results affected patients’ beliefs and behaviors. After the trial, each participant was informed about their individual responses to the wheat, gluten, and sham bars. Despite this personalized feedback, most participants did not change their dietary habits. Of the 26 patients who received their results, 17 continued to follow a gluten-free diet.

The decision to continue the diet was mostly driven by a persistent belief that it improved their symptoms and quality of life. Even among individuals who were shown that their symptoms flared up in response to the sham bar, or that they had no reaction to gluten, most maintained their gluten-free lifestyle. This finding highlights how deeply entrenched beliefs about food triggers can be, resisting even direct, personal scientific evidence to the contrary.

Statistically, a lack of significant difference is not equivalent to similarity given the evaluation methods the authors used. Furthermore, this study appears to be underpowered, increasing the likelihood of a false negative result. Their confidence intervals appear to be quite wide, which suggests that if they performed a TOST evaluation, they may confirm similarity, but without an adequate sample size for statistical testing, I’m still not convinced.

And what was this „sham substance“ exactly?

The abstract states only „gluten and wheat free flour“, which may still have been high in FODMAPs or other components likely to cause digestive upset.

Hey thats probably because TRAUMA is their problem. Trauma has been linked to IBS symptoms. 

Textbook gaslighting from the medical world.