Promotion of Bone Formation by Red Yeast Rice in Experimental Animals: A Systematic Review and Meta-Analysis

Objective. To systematically evaluate the effects of red yeast rice (RYR) and its extract on bone formation in experimental animals and to provide reference data for clinical research on the treatment of osteoporosis.Methods. Chinese and English language databases, including Web of Science, PubMed, the Cochrane Library, Elsevier, Google Scholar, SpringerLink, Embase, China National Knowledge Infrastructure (CNKI), Weipu Chinese Sci-tech periodical full-text database (VIP), and Wanfang Data Knowledge Service Platform (Wanfang), were searched from their establishment to February 2020 using the following terms: "hongqu," "red yeast rice," "Monascus purpureus-fermented rice," "bone mineral density," "osteoblast," "osteoporosis," and "animal models." After excluding nonrelevant articles, Review Manager 5.2 was used to evaluate article quality and to analyze the data. Outcome indicators included bone mineral density (BMD), osteoblast proliferation, and the expression of alkaline phosphatase (ALP).Results. A total of 11 randomized controlled trials were included in the meta-analysis, all of which were animal studies. Six studies included data on BMD, five on osteoblast proliferation, and six on the expression of ALP. The results of the meta-analysis showed that RYR can significantly improve BMD (standardized mean difference (SMD) = 3.12, 95% confidence interval (CI) 1.41 to 4.83, P = 0.0003), promote osteoblast proliferation (SMD=1.64, 95% CI 1.04 to 2.23, P < 0.00001), and increase ALP expression in rats (SMD=1.25, 95% CI 0.69 to 1.80, P < 0.00001).Conclusions. RYR can promote bone formation in experimental animals and may be useful for the treatment of osteoporosis.