Effects of phytoestrogen genistein on cytogenetic biomarkers in postmenopausal women: 1 year randomized, placebo-controlled study

To evaluate in a twelve-month, randomized placebo-controlled study whether pure administration of phytoestrogen genistein (54 mg/day) might reduce cytogenetic biomarkers in peripheral lymphocytes of postmenopausal women. A total of 57 postmenopausal women met the criteria and were randomly assigned to receive phytoestrogen genistein (n = 30) or placebo (n = 27). There was no significant difference in age, length of time since menopause or body mass index between the two groups. After one year, plasma genistein level was 0.14 ± 0.01 μmol/L in the control group and 0.72 ± 0.08 μmol/L in the genistein group (P < 0.0001). At baseline, sister chromatid exchange rate was 4.97 ± 2.17 in the control group and 4.96 ± 1.83 in the genistein group (P = 0.89). After one year, sister chromatid exchange rate was 4.96 ± 2.16 in the control group and 3.98 ± 1.14 in the genistein group (P < 0.05). High frequency cells count was 3% in the genistein group and 5% in the control group (P < 0.05) at the end of the study. Chromosomal aberration frequency was 5.55% in the control group at time 0 and 5.75% in the genistein group; after one year, the figures were 5.86% in the control group and 4.5% in the genistein group (P < 0.05). After one year, there was a negative relationship between sister chromatid exchange rate and plasma levels (r = − 0.43; P < 0.05) in the genistein group. Phytoestrogen genistein has been shown in postmenopausal women to be effective in the reduction of cytogenetic biomarkers. The protective effect on genoma damage appears to be a particularly promising tool in reducing the risk of cancer.