Polyphenols

Figure 1. The chemical structure of tannic acid, a Polyphenol.

Polyphenols are a large family of naturally occurring organic compounds characterized by multiples of phenol (i.e. carbolic acid) units. Polyphenols are abundant in plants and structurally diverse, and include flavonoids, phenolic acids (e.g. lignans), polyphenolic amides, and others. About 60% of Polyphenols are made up of flavonoids, and another 30% made up of phenolic acids.

Many food sources contain Polyphenols. Examples include:

• Fruits: apples, apricots, black chokeberries, black and red currants, black elderberries, black grapes, blackberries, blueberries, cherries, grapes, grapefruit, lemon, nectarines, peaches, pears, pomegranate, plums, raspberries, strawberries
• Vegetables: artichokes, asparagus, broccoli, carrots, endives, potatoes, red chicory, red lettuce, red and yellow onions, spinach, shallots
• Legumes: black beans, tempeh, tofu, soybean sprouts, soy meat, soy milk, soy yogurt, white beans
• Nuts and Seeds: almonds, chestnuts, hazelnuts, flax seeds, pecans, walnuts
• Grains: oats, rye, whole wheat
• Herbs and Spices: caraway, celery seed, cinnamon, cloves, cumin, curry powder, dried basil, dried marjoram, dried parsley, dried peppermint, dried spearmint, lemon verbena, Mexican oregano, rosemary, sage, star anise, thyme
• Other: black tea, capers, cocoa powder, coffee, dark chocolate, ginger, green tea, olives and olive oil, rapeseed oil, red wine, vinegar

As a dietary supplement, Polyphenols are often promoted for overall health and wellbeing. Polyphenols are promoted as "lifespan essentials" and may reduce risk of chronic diseases. The health benefits are attributed to the antioxidant and anti-inflammatory capabilities of Polyphenols. Polyphenol supplements may help with lowering blood sugar levels (by stimulating secretion of insulin), risk of heart diseases (antioxidant and anti-inflammatory action), risk of cancer, promoting healthy digestion (encouraging growth of Bifidobacteria and fighting off harmful bacteria), and boosting focus and memory (e.g. Gingko Biloba).