Advances in Protein-Based Dietary Interventions for Postoperative Recovery in Older Adults and Age-Friendly Functional Foods

With the accelerating changes in the global population structure, older surgical patients are at an increased risk of postoperative malnutrition and sarcopenia. Hypercatabolism triggered by surgery, impaired gastrointestinal digestion and nutrient absorption, and perioperative gut microbiota dysbiosis are key factors contributing to disrupted protein homeostasis and accelerated skeletal muscle loss in older adults. Precision nutritional intervention strategies based on proteins of superior quality derived from food sources and bioactive peptides for promoting postoperative recovery in older patients were systematically summarized. The underlying molecular mechanisms were emphatically analyzed, including the complementary digestive kinetics of proteins originating from diverse sources, efficient transmembrane absorption of oligopeptides via the peptide transporter 1 (PepT1), activation of the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway by branched-chain amino acids to stimulate muscle protein synthesis, and maintenance of homeostasis within the communication axis between the gut-muscle axis. Furthermore, considering the pathophysiological characteristics of dysphagia, impaired mastication, and reduced appetite in older adults, processing technologies and formulation strategies of functional foods for postoperative older adults were systematically summarized, including texture modification through rheological regulation for foods tailored to older demographics, as well as flavor optimization technologies such as controlled enzymatic hydrolysis and covalent encapsulation of bioactive oligopeptides. Finally, current challenges in achieving synergistic intestinal barrier repair, maintaining processing stability, and improving targeting precision were discussed. Future perspectives, including customized rheological design for foods suitable for the elderly, delivery systems targeting specific sites with enhanced stability, and extensive clinical validation, were also proposed to provide scientific guidance for the development of precision nutritional intervention products for postoperative recovery in older adults.