How Not to Die: Discover the Foods Scientifically Proven to Prevent and Reverse Disease

by Michael Greger

The first double-blind, randomized, placebo-controlled gluten challenge was published in 2011. Patients complaining of irritable bowel–type symptoms who claimed they felt better on a gluten-free diet—despite not having celiac disease—were tested to see if they could tell if bread and muffins they were given contained gluten or were gluten-free. All the subjects started out gluten-free and symptom-free for two weeks, and then were challenged with one of the two types of bread and muffins. Even those who ate the gluten-free placebo products felt worse, meaning they started out on a gluten-free diet and continued on a gluten-free diet, yet they reported feeling crampy and bloated. This is what’s called the nocebo effect. The placebo effect takes place when you give patients something useless and they feel better; the nocebo effect occurs when you give someone something harmless and they feel worse. Nevertheless, the subjects who received actual gluten felt even worse. So the researchers concluded that non-celiac gluten intolerance may indeed exist.