Want to have some information regarding the antioxidants usually observed in food items?
No food compounds have been proved with antioxidant efficacy in vivo other than for dietary antioxidant vitamins – vitamin A, vitamin C and vitamin E. It would be beneficial for us to know that regulatory agencies like the Food and Drug Administration of the United States and the European Food Safety Authority (EFSA) have published guidance prohibiting food product labels to claim an inferred antioxidant benefit when no such physiological confirmation is present. Plenty of food items have a high polyphenol content. But, polyphenols have antioxidant properties only in test tube studies. Many studies have revealed that dietary polyphenols have very little or no direct antioxidant food value following digestion. The fate of polyphenols in vivo shows they are feebly absorbed (less than ~4.5%). Catechol group present in many polyphenols, acts as an electron acceptor and is therefore responsible for the antioxidant activity. However, upon uptake in the human body, this catechol group undergoes extensive metabolism for example by catechol-O-methyl transferase, and is consequently no longer capable to perform as an electron acceptor.
Polyphenols are usually obtained from a) Isoflavones (soy beans, tofu, lentils, peas and milk), b) Flavonols (citrus fruits, red wine, onions and apples), c) Catechins (tea, green tea, cocoa, dark chocolate), d) Anthocyanins (berries, red wine) and e) Chlorogenic acid (instant and brewed coffee). Representative spices high in polyphenols (confirmed from in vitro studies) are cinnamon, clove, turmeric, cumin, parsley, oregano, basil, curry powder, mustard seed, ginger, pepper, chili powder, paprika, garlic, coriander, onion and cardamom. Whereas, classic examples of herbs high in polyphenols are sage, marjoram, thyme, tarragon, savory, oregano, peppermint, basil and dill weed. Polyphenol content is significantly high in pigmented fruits like cranberries, plums, blueberries, raspberries, strawberries, blackberries, figs, blackcurrants, cherries, grape juice, guava, oranges, mango and pomegranate juice. High antioxidant content is also observed in avocados, asparagus, broccoli, artichokes, cabbage, beetroot, spinach and in typical nuts (walnuts, pecans, almonds, pistachio, hazelnuts, cashew nuts and macadamia nuts).
