Almond, Hazelnut, and Pistachio Skin: An Opportunity for Nutraceuticals

Nuts are dry, single-seeded fruits, with a combination of beneficial compounds that aid in disease prevention and treatment. This review aims to summarize the antioxidant components and the nutraceutical properties and applications of hazelnut, almond, and pistachio skins, as well as discuss their ability to prevent and treat specific diseases based on in vitro and in vivo studies. The search strategy included searching PubMed database and Google Scholar for relevant articles published in English. Research articles focusing on hazelnut, pistachio, and almond were included. The nut skin extracts were considered and other by-products were excluded from this search. Pistachio and almond skin hydroalcoholic extracts have antibacterial effects and decrease the risk of liver cancer by eliminating reactive oxygen species. Moreover, hazelnut skin can lower plasma against low-density lipoprotein-cholesterol, thus reducing the risk of colon cancer, and its polyphenolic extract can also decrease the formation of advanced glycation end products in vitro with multidimensional effects. Overall, hazelnut, pistachio, and almond skins are a great source of antioxidants, making them suitable for nutraceuticals’ development.