The effect of a soy rich diet on the vaginal epithelium in postmenopause: a randomized double blind trial

Background: A traditional asiatic phytoestrogen-rich diet is associated with a lower incidence of estrogen-dependent cancers and clinical consequences of postmenopausal estrogen deficiency. First Wilcox in 1990, showed an increase of the vaginal cell maturation with phytoestrogens on postmenopausal women, but this has not been confirmed in some subsequent studies. Methods: In this study, we analyzed the effects of a 6-month soy-rich diet on the vaginal epithelium of asymptomatic postmenopausal women in a randomized clinical trial. 187 women were recruited for the study and divided into three groups: a phytoestrogen rich diet group; a hormonal replacement group, and a control group. A vaginal sample for hormonal cytology was taken before and at the end of the study, and sent unnamed to a cytologist. Results: The karyopycnotic index (KI) increased significantly in the diet group and in the HRT group but not in the control group. The maturation value (MV) had an identical trend to the KI. Conclusion: We conclude that a soy rich diet is efficacious in increasing the maturation indices of vaginal cells. This effect could be a useful marker of the efficacy of a dietary intervention with phytoestrogen rich foods, and should be considered during preventive interventions against menopausal effects and vaginal atrophy. (C) 2003 Elsevier Ireland Ltd. All rights reserved.