Effect of Herbal Medicine on Bone Turnover Markers in Pre- and Peri/postmenopausal Women: An Overview of Meta-Analyses

Abstract

Background: Osteoporosis is a chronic debilitating disease that poses a serious challenge to humanity. Osteoporosis and its related complications impose huge direct costs on the health system. Objectives: The purpose of this study was to critically evaluate the effects of soy isoflavones and phytoestrogens on bone turnover markers in pre- and peri/postmenopausal women. Methods: Three main databases [MEDLINE, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL)] were searched to explore published meta-analyses. The methodological quality was assessed by AMSTAR. Results: Four meta-analyses were included in this overview. Isoflavones and phytoestrogens significantly decreased urinary pyridinoline (Pyd). The subgroup analysis of Pyd indicated that isoflavones were more effective in overweight/obese individuals, and a dosage of < 90 mg/day Deoxypyridinoline (Dpyd) had a desirable effect on phytoestrogens. However, the findings regarding the effect of isoflavones on Dpyd were controversial. The subgroup analysis of Pyd showed that isoflavones in the form of extract and tablet caused a significant decrease; nevertheless, soy foods with isoflavones and isolated soy protein failed to induce a significant drop. Isoflavones decreased Dpyd even during the intervention but were unable to induce a significant decrease. Moreover, although isoflavones considerably reduced Dpyd in postmenopausal women, it was non-significant in peri-menopausal women. The bone formation markers of bone-specific alkaline phosphatase, N-telopeptide, and osteocalcin were not significantly different between soy isoflavones and the control group. Osteoprotegerin was significantly higher, and C-telopeptide was significantly lower in women receiving isoflavones than in women in the control group. Conclusions: The current overview showed that isoflavones might decrease some urinary bone resorption markers. However, it had no significant effect on bone formation markers and influenced turnover markers in menopausal women.