There is little doubt that some people have an intolerance to gluten and that a gluten free diet is an appropriate way to address this. However, the gluten free diet is also associated with pseudoscience in terms of what it can achieve and how it is diagnosed.
Take, for example, the recent news that tennis player, Novak Djokovic, has embraced a gluten free diet on the advice of his nutritionist. According to a recent article by Dr Joe Schwarcz, Djokovic was diagnosed as follows:
Djokovic’s “nutritionist” asked him to stretch out his right arm while placing his left hand on his stomach. He then pushed down on the tennis champion’s right arm and told him to resist the pressure, which he was able to do. Next, Djokovic was asked to hold a slice of bread against his stomach with his left hand while the nutritionist again tried to push down on his outstretched right arm. This time, he was able to push it down easily. The demonstration, Djokovic was told, showed that he was sensitive to gluten, which is why he had suffered so many mid-match collapses in his career.
Some readers will be aware of this “applied kinesiology” approach where the apparent “weakness” is the result of adjusting the angle of the pressure applied by the practitioner, not by the presence of a slice a bread. Hardly an appropriate method for diagnosing any disease or disorder.