Carotenoids are pigments in plants, algae, and photosynthetic bacteria. These pigments produce the bright yellow, red, and orange colors in plants, vegetables, and fruits. Unlike some protein-rich foods and vegetables, cooking and chopping carotenoid-rich foods increase the strength of the nutrients when they enter the bloodstream. Foods rich in carotenoids include kale, spinach, watermelon, bell peppers, and carrots to name a few. They are beneficial antioxidants that can protect you from disease and enhance your immune system.