Role of food proteins and bioactive peptides in inflammatory bowel disease

Inflammatory bowel disease (IBD) comprises a group of chronic inflammatory disorders of the gastrointestinal tract which precise aetiology remains unknown. Diet is one of the main environmental factors involved in IBD as it modulates both the gut microbiota and the mucosal immune system. The gastrointestinal tract is therefore the main target of bioactive compounds, such as food-derived bioactive peptides. The present review provides an overview on the physiological relevance of food proteins, hydrolysates and peptides in the digestive system and explores the preventive and therapeutic role that they can play in IBD. Findings and insights from studies on cell cultures, animal models and human clinical trials are summarised and discussed. The gastrointestinal mucosa presents unique mechanisms of immune tolerance towards nutrients and commensals under a delicate balance, which is nevertheless dysregulated in IBD. Counteracting this imbalance, dietary peptides carry a range of biological activities that might provide positive impact on gastrointestinal homeostasis. The anti-inflammatory, antioxidant and immunomodulatory properties of peptides from diverse food sources has been broadly evaluated in vitro. Protective mechanism of action through modulation of the pro-/anti-inflammatory and tolerogenic profile of immune responses has been demonstrated in animal models both in resting conditions and in IBD-like inflammation. However, there is still limited evidence in the human setting to support their bioactivity. This review highlights the impact of bioactive peptides in gastrointestinal health and encourages more robust information in clinical trials to ultimately elucidate their role as functional compounds in human IBD.