Food Sources of Polyphenol

Polyphenolic compounds, or polyphenols, are natural plant metabolites that have antioxidant properties in humans. The U.S. Department of Agriculture has not yet established a recommended daily intake for polyphenols or calculated current average polyphenol consumption in America. Polyphenols are categorized as either phenolic acids, flavonoids or tannins, all of which are antioxidants. Only eating a variety of food sources of polyphenol provides access to all three types.

Fruit

The most popular source of polyphenols, primarily flavonoids and tannins, is fruit. Dark red fruits have the highest concentration of polyphenols, particularly dark plums, cherries and berries. Strawberries, blueberries and raspberries are a good source of ellagic acid, a tannin. Apples, grapes, pears, cantaloupe and cranberries are also good sources of polyphenol antioxidants.

Vegetables

Vegetables generally have much lower polyphenol concentration than fruits. Onion, broccoli, cabbage, celery, and parsley are reliable sources of flavones and flavonols, types of flavonoids. Red-tinted vegetables like beets, cabbage and rhubarb are highest among vegetables in overall polyphenol content.

Grains and Legumes

Whole grains foods and legumes are often paired because they complement each other in forming a complete protein. Both are also good sources of polyphenols. Most legumes, including beans, peas and nuts, contain flavonoids. Soybeans are a common source of isoflavones, another type of flavonoids. Whole grain foods, oats and rye also contain polyphenols, particularly phenolic acids.

Chocolate and Coffee

Two of American's favorite treats, chocolate and coffee, have also been found to contain significant quantities of phenolic acids, a type of polyphenol. In fact, after grain products, coffee is believed to be the greatest source of polyphenols in the American diet. Coffee and cacao are rich in caffeic acid and ferulic acid, two polyphenol antioxidants. The polyphenol content in chocolate is directly related to its cacao content, with dark chocolate having much more than milk chocolate.

Red Wine

Another favorite source of polyphenol antioxidants is red wine. White wine does not sit on the skins of the grapes and therefore does not receive nearly as much of the phytonutrients as occur in red wine. Of course, all alcohol products have to be consumed in moderation. Nevertheless, the tannins and flavonoids available in red wine are believed to explain why the French have low incidence of heart disease despite a diet high in saturated fat.

References

• Phytonutrient FAQs
• Daily Polyphenol Intake in France from Fruit and Vegetables
• Boosting Your Polyphenols

Resources

• Polyphenols in Red Wine
• Teaming Up with Polyphenolic Flavonoids