Phytoestrogens and prostate cancer risk.
BACKGROUND
Phytoestrogens are natural plant substances. The four main classes are isoflavones, flavonoids, coumestans, and lignans. Phytoestrogens have anti-carcinogenic potential. For evaluation of the effect of phytoestrogens on prostate cancer risk, we reviewed analytical epidemiological data.


METHODS
Up to now, there are few studies that have assessed the direct relation between the individual dietary intake of soy products and other nutrients with phytoestrogens and the risk of prostate cancer. We decided to review analytical epidemiological studies providing data on (a) dietary soy intake or flavonoids intake, (b) urinary excretion of isoflavones or lignans, or (c) blood measurements of isoflavones or lignans. Soy is used as a marker for isoflavone intake.


RESULTS
Overall, the results of these studies do not show protective effects. Only four of these studies are prospective, and none of them found statistically significant prostate cancer reductions. Two prospective studies measured flavonoid intake and one reported a preventive effect on prostate cancer for the assumption of myricetin. One study assessed enterolactone concentrations in three different countries and showed no reduction in prostate cancer occurrence.


CONCLUSIONS
Few studies showed protective effect between phytoestrogen intake and prostate cancer risk.
Ganry
O
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Medical information, Epidemiology and Biostatistics, Hôpital Nord, Place Pauchet, University Hospital of Amiens, 80 054 Amiens cedex 1, France.ganry.olivier@chu-amiens.fr
D017677:Age Distribution; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D019587:Dietary Supplements; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D048789:Phytoestrogens / Q000378:metabolism*; D028321:Plant Preparations / Q000627:therapeutic use*; D011379:Prognosis; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000503:physiopathology / Q000517:prevention & control*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D015996:Survival Rate
D048789:Phytoestrogens; D028321:Plant Preparations