Fish oil is considered a healthy food due to the presence of large amounts of polyunsaturated fatty acids, especially EPA and DHA. Fish oil dietary supplements are usually in triacylglycerol (TAG) and ethyl ester (EE) forms. The main forms of EPA/DHA in marine foods are TAGs and phospholipids (PLs). PL forms and traditional fish oil supplements have different nutritional functions and constitute the most popular research topics within EPA/DHA-enriched structural lipids. Moreover, there is an increasing number of high-purity DHA or EPA products; therefore, it is essential to clarify the differences in physiological activity between DHA and EPA, as well as the differences in disease treatment and prevention, exploring new physiological regulatory functions and analyzing their molecular mechanisms. In recent years, researchers have also focused on the structural modification and derivatives of EPA/DHA. Such studies will contribute to the development and applications of fish oils as functional foods. The aim of this Special Issue is to highlight the potential of marine fish oils as functional foods. We welcomed all original research articles, reviews, perspectives, and method papers that focus on, but are not limited to, the following themes: The structure-activity relationship of fish oil in different molecular species to maintain human health and prevent chronic disease; The evaluation of novel functions and an analysis of the possible underlying mechanisms of high-purity DHA or EPA; To explore the impact of fish oil on human health at different stages of the life cycle, such as early-life nutrition.
