Bioactive compounds are nutrients and non-nutrients present in the food matrix (vegetal and animal sources) that can produce physiological effects. They are compounds that have an effect on a living organism, tissue, or cell, usually demonstrated by basic research in vitro or in vivo in the laboratory. Bioactive compounds are commonly derived from plants, animal products, or can be synthetically produced. Examples of plant bioactive compounds are carotenoids, polyphenols, or phytosterols. Examples in animal products are fatty acids found in milk and fish. Other examples are flavonoids, caffeine, choline, coenzyme Q, creatine, dithiolthiones, polysaccharides, phytoestrogens, glucosinolates, and prebiotics.

Bioactive compounds are considered as non-nutritional but vital components of food. They are extranutritional constituents that typically occur in small quantities in foods. Bioactive compounds have not been proved to be essential, as the body can function without them, or because their actions are obscured by nutrients fulfilling the function. However, they have been shown to have a positive impact on health and disease prevention.