One study showed that cocoa and dark chocolate contained more antioxidant activity, polyphenols and flavanols than other fruits they tested, which included blueberries and Acai berries (2). Bottom Line: Cocoa and dark chocolate have a wide variety of powerful antioxidants, way more than most other foods.

7 Proven Health Benefits of Dark Chocolate - Healthline
https://www.healthline.com/nutrition/7-health-benefits-dark-chocolate