The Effect of Selected Herbal Medicines on Bone Turnover Markers: A Systematic Review and Meta-Analysis

Objective: To evaluate systematically the therapeutic effects of five herbal medicines (curcumin, black seed, ginger, cinnamon, and flaxseed oil) on bone turnover markers as a primary outcome. Materials and methods: A comprehensive systematic search of the literature was conducted in the electronic databases consisting of the Cochrane Library, MEDLINE, Web of Science, Scopus, Embase, ProQuest, and Google scholar, as well as SID, Magiran, and Irandoc for Persian literature up to December 2020. All Randomized controlled trials and quasi-experiments evaluated the impact of studied herbal medicines on bone turnovers of Bone Specific Alkaline Phosphatase (BSAP), osteocalcin, C-terminal Telopeptide type 1 Collagen (CTX-I), Deoxypyridinoline (DPD) were analyzed. Results: Sixteen interventional studies comprised 968 participants included in systematic review. Ten of eligible studies with 603 participants included in meta-analysis. Curcumin, black seed and flaxseed did not have a significant effect on BSAP (SMD=-1.76, 95%CI: -6.85 to 3.33, p=0.50, I²=0.99, 6 trials, 241 participants), CTx (SMD=-0.17ng/mL, 95%CI:-0.43 to 0.09, p=0.21, I²=1.000, 5 trials, 216 participants), DPD (MD=0.82nmol/mmol, 95%CI:-0.05 to 1.68, p=0.06, I²=0.000, 2 trials, 67 participants), osteocalcin (SMD=-2.02ng/mL, 95%CI:-4.49 to 0.45, p=0.11, I2=0.79, Six trials, 229 participants). As secondary outcomes, femoral neck Bone Mineral Density (BMD) increased significantly (p=0.03, I²=0.12) but lumbar spine BMD didn't differ (p=0.28, I2=0.97). Curcumin significantly increased total hip BMD (p<0.001, I²=0.12). QiangGuYin containing cinnamon as a combined Chinese medicine had significant effect on P1NP, β-CTx, and BMD. Conclusion: Studied herbs except for QiangGuYin had no significant effects on bone turnover markers. Due to high heterogeneity between trials, further high-quality trials are suggested.