The antioxidant quercetin is partially responsible for that lovely red glow in your apple skin. It is also present in many other fruits, nuts, vegetables and grains.²⁴ Many of the foods high in quercetin are full of lots of other important nutrients, such as vitamins A, C, and E, calcium, magnesium, and lycopene.⁷

You may want to consider organically grown versions of fruits and vegetables when looking to maximize your quercetin intake. A recent study found that tomatoes which had been organically grown had more quercetin than their conventionally grown counterparts, although green peppers had no difference in quercetin levels.²⁵ Often different parts of the fruit or vegetable contain higher amounts of quercetin, such as apple skin and the outermost layers in onions.^26-27