Nutritional and bioactive properties of native chicken eggs: Global perspectives on human health implications

Eggs are increasingly recognized not only as nutrient-dense foods but also as sources of bioactive compounds with potential physiological relevance. Native chicken eggs, produced under diverse genetic backgrounds and often under low-input production systems, may exhibit compositional characteristics that differ from those of commercial layer eggs. This review summarizes the major bioactive compounds of native chicken eggs and critically evaluates the current evidence regarding their possible implications for human health. Yolk phospholipids and omega-3 fatty acids have been associated with pathways related to lipid metabolism and membrane function, whereas carotenoids such as lutein and zeaxanthin exhibit antioxidant properties and have been discussed in relation to visual function. Albumen proteins, including lysozyme, ovotransferrin, and ovomucoid, have demonstrated antimicrobial and immunomodulatory activities mainly in experimental settings. Some studies have reported that native chicken eggs contain higher levels of antioxidant micronutrients and distinctive lipid profiles compared with commercial eggs, although such differences are not consistent and may vary with breed, diet, and production systems. Overall, native chicken eggs represent a potentially valuable food resource beyond basic nutrition. However, current evidence for their proposed cardiometabolic, antioxidant, and immune-related effects is derived largely from compositional analyses and from in vitro or animal studies, with only limited evidence in humans. Future research integrating multi-omics approaches, standardized comparative designs, and well-controlled human studies is needed to assess whether the compositional and experimental findings reported for native chicken eggs translate into meaningful benefits in humans and to their development as value-added functional food products.