nts that have beneficial biological activity in humans. Flavonoids are polyphenols that share a similar basic chemical structure. Some are pigments responsible for the bright colors of many fruits and vegetables. Flavonoids, which include resveratrol, proanthocyanidin, quercetin and catechin, may be at least partly responsible for the health benefits of a diet rich in fruits and vegetables. All of these compounds are powerful antioxidants that can destroy free radicals. According to the University of Maryland Medical Center, they also suppress tumor growth, help prevent inflammation and reduce the likelihood of blood clots. They may also boost the immune system, helping you avoid allergic reactions and infection, and they may prevent or reduce high blood pressure and lower your risk for certain cancers.
A single type of fruit or vegetable often contains several different bioflavonoids, but certain foods are especially rich in a particular compound. For example, red grapes, wine and olive oil are exceptionally rich sources of resveratrol, while apples and red, blue and purple berries contain abundant anthocyanidin. Catechins are found in green tea, apples and grapes, while quercetin-rich foods include citrus fruits, red onions, parsley, red apples consumed with their peels, apricots, dark cherries and darker types of berries. Although it is not known precisely how cooking affects the flavonoid content of food, some methods such as boiling may reduce the levels of certain compounds. For this reason, consume flavonoid-rich fruits and vegetables raw or steam them lightly whenever possible.
- University of Maryland Medical Center: Vitamin C (Ascorbic Acid)
- Linus Pauling Institute: Vitamin C
- University of Maryland Medical Center: Vitamins -- Phytochemicals
- Linus Pauling Institute: Flavonoids
- Office of Dietary Supplements: Vitamin C
- University of Maryland Medical Center: Quercetin
- Journal of Nutritional Science and Vitaminology: Various Cooking Methods and the Flavonoid Content of Onion
- fruit & vegetables on the outside steps of a shop in santorini image by Antony McAulay from Fotolia.com