Vegetables
Polyphenols found aplenty in green vegetables are responsible for giving them their green color. So 'go green', when it comes to boosting your polyphenolic content. Green vegetables, like artichoke, kohlrabi, spinach, kale, turnip, lettuce, broccoli, watercress, and zucchini are some of the richest sources of polyphenol antioxidants. Other vegetables that have high concentration of polyphenols are eggplant, red cabbage, sweet potatoes, and onions.