Glutamine Peptides: Preparation, Analysis, Applications, and Their Role in Intestinal Barrier Protection

Background: Glutamine peptides refer to a series of peptides containing glutamine, and the activity of glutamine peptides is characterized by the content of non-nitrogen terminal glutamine in the peptide. It has been found that glutamine peptides are a stable substitute for glutamine monomer, and they are increasingly studied in nutrition and physiology due to their functional properties. Methods: An extensive search of the literature was conducted in the PubMed, Web of Science, Scopus, and Google Scholar databases up to December 2024. Inclusion criteria focused on the role of glutamine peptides in intestinal health, and the included literature was screened and summarized. Results: This study systematically reviews the current status of research on the preparation, analysis, applications of glutamine peptides and their role in intestinal barrier protection. Furthermore, the challenges faced by the current research and the development direction in the future are discussed. Conclusions: Glutamine peptides can play a role in protecting the intestinal barrier by regulating tight junctions, mucin, inflammatory response, and intestinal flora. In addition, further and intensive investigations are urgently required to address the current challenges pertaining to the structure-activity relationships of glutamine peptides and their transport and absorption mechanism in the gut. This review contributes to a better understanding of the mechanism of glutamine peptides to protect intestinal barrier function and also provides a reference for the development of functional foods with protective effects of intestinal barrier function.