The role of dietary wheat in functional dyspepsia: defining an overlap with gluten or wheat sensitivity

This thesis aims to define an overlap between wheat sensitivity and functional dyspepsia, and postulates a potential role for duodenal eosinophils as a histopathological link between the two conditions. It includes several published reviews and original research articles which outline and extend the literature pertaining to these two conditions. Firstly, it outlines in several narrative reviews our current understanding of non-coeliac wheat sensitivity and functional dyspepsia, as well as the role of eosinophilic inflammation in the gastrointestinal tract. Secondly, the epidemiology of wheat sensitivity in Australia and its association with functional dyspepsia at a population level is defined in two large population studies. These studies also detail the phenomenon of wheat avoidance and its association with chronic gastrointestinal symptoms. In coeliac disease, a strict gluten free diet is necessary given the risks of serious health consequences such as osteoporosis, as demonstrated in a large population study from the Hunter Valley in the third section of the thesis. However, nutritional concerns including its effect on cardiovascular risk factors, systematically reviewed in an included study, suggests even if a gluten free diet is efficacious in functional dyspepsia (which is not yet established) there are potential risks. In the fourth section the role of duodenal eosinophils as a potential histopathological link between wheat ingestion and dyspeptic symptoms is explored regarding coeliac disease. A pilot interventional study in the final section details the effectiveness of a wheat free diet in the treatment of functional dyspepsia.