Phenolic acids are divided into two groups: hydroxycinnamic acids (hydroxycinnamates) (for example, ferulic acid or caffeic acid) und hydroxybenzoic acid (z. B. gallic acid or ellagic acid).
The highest concentrations of phenolic acids can be found in the outer layers and skins (husks, hulls) of plants. There, they provide cell wall stability. When the outer layers, leaves, skins (husks, hulls) are discarded and unused, phenolic acids content is significantly reduced in plant based foods. For example, a kilogram of whole wheat flour contains 500 mg of ferulic acid, whereas the same amount of white flour only contains 50 mg. Therefore, 5 g of ferulic acid is contained in a kilogram of wheat bran.
- Antioxidant (meaning, they prevent sensitive molecules’ reaction with oxygen).
May reduce the risk of:
- Certain cancer diseases such as oesophagus cancer, stomach cancer or lung cancer.
Ferulic acid: whole grains
Caffeic acid: coffee, potatoes (skin/peelings)
Gallic acid: red and white wines
Ellagic acid: nuts (walnuts, pecans) and berries
Vegetables (kale, white cabbage, green beans, spinach and lettuce) and fruits (apples and blueberries) are also rich in phenolic acids.
It should be noted that:
Removal of skins and outer leaves reduces the phenolic acids content in plant based foods.
Recommendations for daily requirements have not yet been scientifically determined.
Phytochemicals should not be taken as isolated in tablets because this may cause undesirable side effects. The numerous other ingredients in food are most likely essential, in order that they can exert healthy effects on the body.