Turtle shell as a health food ingredient: a review of global utilization, nutritients, health benefits, and functional food potential

In recent years, with the rapid growth of global turtle farming, turtle shell, as a major by-product, has been used in traditional medicine and health foods, gaining increased attention for its nutritional and bioactive value. This review systematically summarized the classification and global utilization of turtle shells, as well as the regulatory policies on its use. From a “component–activity–product” perspective, its key nutrients, health benefits, and application prospects in relation to health food development were reviewed. Global research on turtle nutrition and health has shown regional variations, shaped by conservation needs and international regulations. While Western countries like the United States, Brazil, and Australia emphasized the nutritional value of turtle fat, China has focused on the health benefits of turtle shell as a by-product. Moreover, turtle shells contain proteins, amino acids, minerals, fatty acids/esters, steroids, peptides, and polysaccharides, providing anti-inflammatory, antioxidative, immunomodulatory, hematopoietic, and blood pressure- and lipid-regulating effects. Moreover, they can potentially treat osteoporosis, Parkinson’s disease, Alzheimer’s disease, and liver cancer. They have also been used in products like beverages, turtle jelly, gelatin, starch-based foods, and medicinal wines. However, future research should investigate its health benefits based on composition or determine the active compounds from bioactivities, supporting its development into functional foods and therapeutics. • Western studies focus on turtle fat; China emphasizes shell health benefits. • Conservation policies limit research on turtle shell nutrition and function. • Hot water-assisted enzymolysis improves collagen yield from turtle shell. • Health benefits: Anti-inflammation, bone-supporting, antitumor, neuroprotection, etc. • Rich in protein and calcium, with strong potential in functional food development.