Phenolic Acids

Phenolic acids are one category of phytochemicals called polyphenols. They're found in a variety of plant-based foods; the seeds and skins of fruits and leaves of vegetables contain the highest concentrations. Phenolic acids are easily absorbed in your intestinal tract, and may be beneficial to your health because they work as antioxidants that prevent cellular damage due to free-radical oxidation reactions. They may also have anti-inflammatory properties.

Phenolic acids are abundant in a balanced diet, as long as you consume adequate amounts of fruits, vegetables and whole grains. Sources include mangos, berries, apples, citrus fruits, plums, cherries, kiwis, onions, tea, coffee, red wine, and wheat, rice, corn and oat flours. There are many different phenolic acids and they can be divided into two categories: benzoic acid derivatives such as gallic acid, and cinnamic acid derivatives, including caffeic acid and ferulic acid. The cinnamiac acids are more common.

Gallic acid is found in tea and grape seeds. Coffee contains caffeic acid and chlorogenic acid. Blueberries, kiwis, plums, cherries and apples contain large amounts of caffeic acid. Red wine and citrus fruits contain cinnamic acid. Ferulic acid is found in the outer coverings of cereal grains. Corn flour has the most ferulic acid, and whole grain wheat, rice and oat flours are good sources as well.

Foods rich in phenolic acids may be beneficial for your health, but it's difficult to understand how much of that benefit is due to the phenolic acids, or to the nutrients, fiber and other photochemicals also found in those foods. For example, flavonoids, another category of polyphenols, are often found in the same foods as the phenolic acids, and most fruits and vegetables are rich in nutrients and fiber. Drinking coffee has been associated with a decreased risk of cancer and other chronic diseases. It contains caffeic acid and chlorogenic acid, but it also contains caffeine, and other potentially beneficial compounds. Red wine has phenolic acids, but it also has resveratrol, which is another type of polyphenol.

Phenolic acids may be available as dietary supplements, such as grape seed extract, which contains gallic acid. However, evidence suggests that eating fruits, vegetables and whole grains is more beneficial than taking antioxidant supplements.

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