Factors affecting consumers' adherence to the gluten-free diet, a systematic review

Background: The gluten-free market is expanding rapidly. The reasons for this reflect a growing interest in adopting a gluten-free diet (GFD). This is partly explained by an increasing number of people diagnosed with Celiac Disease (CD), but also because of public perceptions that a GFD is a healthy diet option. However, products specifically marketed as gluten-free (GF) are reduced in several sensorial characteristics, are more expensive, and have lower nutritional values than comparable alternatives. Scope and approach: The aim of this review is to provide an up-to-date set of factors that underpin consumers’ preferences and adherence to GFD. After screening, 54 articles were considered for the review. Key findings and conclusions: The review classifies the factors affecting GFD in eight groups: “Factors specific to the GFD”; “Socio-demographic factors”; “GF products’ factors"; "Psychological Factors"; "Symptoms related to Celiac"; "Celiac Disease’s factors"; "Quality of Life"; "Other Factors". Results on the level of association and significance of the factors affecting adherence to GFD are mixed. Moreover, in the process of reviewing the literature, this review reveals that most of the studies that have investigated factors associated with adherence to GFD are focused primarily on celiac patients while neglecting the fact that many non-celiac adopt the diet. From this we discuss future research directions, and what questions remain unanswered in the domain of adherence to the GFD.