Functional foods, also known as “nutraceuticals,” hold a variety of bioactive substances that, if introduced into a regular diet, cause health enhancement in the population and lower the risk of different diseases. Researchers have been interested in developing tea, coffee, and seafood as functional foods in recent years, driven by the discovery of their extensive biological activity and health advantages. Tea contains polyphenolic components (catechins and epicatechins), flavonol glycosides, theaflavins, theobromine, caffeine, L-theanine, and volatile organic compounds that act as antiinflammatory, antioxidant, and antimicrobial agents and help in the prevention of many illnesses, like cardiovascular diseases, neurodegenerative diseases, and metabolic disorders like diabetes and obesity. Also, the components of coffee beans, like caffeine, kahweol, cafestol, and caffeoylquinic acids (CQAs, chlorogenic acid), hold several health benefits against noncommunicable diseases. Seafoods are also excellent sources of beneficial components like MUFAs, PUFAs, essential amino acids, protamines, nonproteins, phospholipids, carotenoids, and fucoxanthin that have a variety of properties and can lower the risk of various lifestyle-related diseases. The significance of the bioactive components of tea, coffee, and seafood, as well as their potential to promote health through different physiological activities, is emphasized in this chapter.