Effects of flaxseed and Hypericum perforatum on hot flash, vaginal atrophy and estrogen-dependent cancers in menopausal women: a systematic review and meta-analysis

OBJECTIVE In this study, we aimed at evaluation of the efficacy of Hypericum perforatum and flaxseed on hot flash, vaginal atrophy and estrogen-dependent cancers in menopausal women. MATERIALS AND METHODS We searched MEDLINE, Scopus, and the Cochrane Central Register of Controlled Trials (RCT) to explore trials that assessed the effectiveness of H. perforatum and flaxseed on hot flash, vaginal atrophy and estrogen-dependent cancers. In this regard, the following terms were used "menopause AND H. perforatum OR flaxseed OR Linum usitatissimum. Only randomized controlled trials were included in the study. RESULTS Nine RCTs were included in this systematic review. Based on the literature, flaxseed showed beneficial effect on hot flash frequency and intensity, which was not statistically significant. According to two trials, flaxseed showed estrogenic effects; however, no conclusion regarding cancer promoting or protecting effects can be made. The evidence of the efficacy of the flaxseed on alleviating vaginal atrophy was also limited due to inconsistent findings in this regard. One trial declared that Vitex agnus-castus and H. perforatum showed comparable decrease in the frequency of hot flashes. CONCLUSION The results of our systematic review suggest beneficial effect on vasomotor symptom with both of flaxseed and H. perforatum. Consistent conclusion regarding estrogen-dependent cancers and maturation value is limited due to small number of trials related to flaxseed. Further trials are still needed to confirm the results of our systematic review.