Soy isoflavone supplementation in healthy men prevents NF-kappaB activation by TNF-alpha in blood lymphocytes.

Author: Davis JN et al.
Publication: Free Radic Biol Med 2001;30:1293-1302.

The purpose of this study is to investigate the association between intake of soy and a decreased cancer risk. It is believed that soy isoflavones are the anti-cancer compounds but it's not exact mechanism is not yet known.

The soy isoflavones, genistein and daidzein, have antioxidant properties and it's believed that the anti-cancer effect is linked to this antioxidant effect. Previous in-vitro studies have shown demonstrated that the soy isoflavone genistein, but not daidzein inhibits the activation of the redox-sensitive transcription factor, NF-kappaB, in prostate cancer cells. In-vivo test also showed that 50 mg isoflavones mixture, consumed twice daily for 3 weeks have effect on the NF-kappaB activation in the blood lymphocytes. Isoflavones supplemention also resulted in a reduction of 5-hydroxymethyl-2'-deoxyuridine, a marker for oxidative DNA damage.

This preliminary study demonstrates that soy isoflavone may protect cells from oxidative stress and decreasing DNA adduct levels.