Supplementation with the soy isoflavone genistein could reduce tissue biomarkers of prostate cancer after just a few weeks, according to new research.
The study reports that supplementation with 30 mg of genistein daily
resulted in a 7.8% decrease in levels of blood serum prostate specific
antigen (PSA) in a matter of weeks. The researchers added that PSA
levels in the placebo arm of the double blind trial increased by 4.4% in
the same time.
«Genistein at a dose that can be easily obtained from a diet rich in soy reduced the level of serum PSA in patients with localized prostate cancer, without any effects on hormones… It was well tolerated and had a beneficial effect on blood cholesterol,» said the researchers.
«Our results indicate a possible therapeutic effect by genistein in early CaP, producing a boderline significant serum PSA reduction and normalization of PSA expression in malignant prostate tissue,» they added.
The researchers conducted a placebo-controlled, randomized, double blind study in 47 men with early prostate cancer and elevated PSA levels.
They noted that although PSA is present in small quantities in the serum of men with healthy prostates, it tends to rise in the presence of prostate disorders, including prostate cancer.
The researchers reported that supplementation with 30 mg of the supplement over a period of three to six weeks, was shown to reduce PSA values in serum. In addition, the supplement was seen to lower blood cholesterol levels.
The daily dose was also shown to be well tolerated, with no effects on hormone levels, such as testosterone.
«Our results indicate that genistein normalize the intra-cellular expression of PSA in CaP epithelial cells. Furthermore, genistein was shown to reduce the level of PSA in serum,» said the researchers.
The researchers said that the findings of the study could help to explain the reduced risk of prostate cancer in men consuming a diet high in soy products, and highlights the potential benefit of a dietary supplement for men.