Updated 14 February 2013

Flavonoids - powerful antioxidants

The blue, blue-red, and violet colours of certain fruits and vegetables can be attributed to flavonoids, powerful antioxidants.


Flavonoids are phytochemicals that form part of the larger phenol group. Phytochemicals are biologically active, health-preserving substances that occur naturally in certain foods.

More than 800 flavonoids have been identified. The blue, blue-red, and violet colours of certain fruits and vegetables can be attributed to this antioxidant.

Like other antioxidants, flavonoids are powerful scavengers that destroy harmful free radicals in the body, thereby reducing cancer risk.

Research also shows that certain dietary flavonoids have the potential to reduce the risk of heart disease.

It looks like flavonoids exert this positive effect mainly in three ways: firstly, by keeping the endothelium (the layer of cells that lines the heart and blood vessels) healthy, thereby reducing the risk of heart attacks; secondly, by lowering blood pressure, which is also related to heart disease; and thirdly, by modulating platelet function in a similar way as aspirin does.

The flavonoids in red wine, and particularly one called resveratrol, may also increase HDL ("good") cholesterol and decrease LDL ("bad") cholesterol levels, researchers say.

Research shows that the flavonoid quercitrin may work to reduce inflammation in the large intestine associated with Crohn’s disease and ulcerative colitis.

Studies have also shown that flavonoids could improve diabetic control. It looks like it does its magic by preventing vitamins C and E from being consumed in oxidative processes. And the flavonoids in cranberries appear to prevent bacteria from sticking to the walls of the bladder, thereby cutting the risk of bladder infection.

Which foods contain flavonoids?

Flavonoids can be found in green tea. It can also be found in broccoli, cabbage, grapes, cranberries, onions, apples, beans and red wine.

Recently, the flavonoids in cocoa, called flavanols, have also made headlines. Cocoa beverages and food rich in flavanols could possibly also thicken skin and reduce reddening, according to recent research.

How much flavonoids do you need?

No formal recommendations for flavonoid intake currently exist. However, given the potential benefits, a diet rich in fruit and vegetables is recommended.

 - (Health24, updated October 2011)

Read more:

Phytochemicals: powerful protectors
Chocolate lovers have fewer strokes
Red wine for heart health


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