This blog is part of the GLIM immunity blog series. What do apples and onions have in common? They both contain a powerful compound called quercetin! Quercetin belongs to a class of compounds known as phytochemicals. Phytochemicals contribute to the color, taste and smell of fruits and vegetables, and we are just beginning to understand their role in maintaining our health. Quercetin is thought to improve elements of mental and physical performance by acting as an antioxidant