Many people consider food diet important in both prostate cancer prevention and in controlling its progression. Dietary derived agents, such as the flavonoids derived from fruits and vegetables should be of particular interest for prostate cancer survivors, as they seem to offer both chemo-prevention and an antioxidant effect along with a favorable safety and side-effect profile.
Flavonoids that are directly derived from fruits and vegetables demonstrate an action on the androgen receptor (AR) axis thus having a particular value for preventing or treating castrate-resistant prostate cancer.
There are four main flavonols – quercetin, myricetin, kaempferol, and fisetin that have been demonstrated in laboratory studies to have chemo-preventive action in both castrate-resistant and castrate-sensitive prostate cancer models. Mechanisms of flavonol action on the AR axis in PCa have been proposed to be the inhibition of the 5?-reductase enzymes, direct androgen competition, suppression of the AR complex and transactivation by coregulators such as c-Jun, Sp1, and the PI3K/Akt pathway. No one knows whether AR axis-mediated effects can fully account for the flavonols’ chemo-preventive action.
Dietary flavonols are found in:
- Blueberries and other Berries
- Citrus Fruits
- Black, Oolong and Green Teas
- Red Wine
- Dark Chocolate (with 70% or more cocoa content)
- Red Skin Peanuts
- Plants (found ubiquitously)
- Ginko biloba
Further information on dietary sources of flavonoids can be obtained from the United States Department of Agriculture flavonoid database at: http://www.ars.usda.gov/Services/docs.htm?docid=24953 on pages 16 to 118.