Nutraceuticals have become quite popular in the last few years because of their physiological and possible health benefits, including their control of lipid metabolism and their anti-inflammatory, antioxidant, anti-cancer, and prebiotic properties. The primary objective of this review was to provide an overview of the key findings from our in vitro and in vivo studies on the effects of the main components of the Mediterranean diet, which include polyunsaturated fatty acids, fruit components, and extra virgin olive oil compounds. The Mediterranean diet is a nutritionally recommended dietary pattern that includes high levels of consumption of nutraceuticals. According to experimental research, the bioavailability, solubility, toxicity, and administration method of nutraceuticals determine their intended therapeutic use. With an emphasis on the gastrointestinal system and recommendations for certain dietary components for individualized adjuvant treatments, this study offers additional in-depth information on the effects associated with the administration of nutraceuticals on human health.