Efficacy of vitamin D fortified foods on bone mineral density and serum bone biomarkers: A systematic review and meta-analysis of interventional studies

Vitamin D fortified foods (VDFs) were taken into consideration due to the high prevalence of osteoporosis worldwide. However, the efficacy of VDFs on bone health has not been fully examined. The current meta-analysis was conducted in order to summarize the impacts of VDFs on serum 25-hydroxyvitamin D (25(OH)D), bone mineral density (BMD), and bone turnover markers (BTM). A systematic search up to October 2017 was done via PubMed and Scopus search engines. To pool mean differences, random-effects model (the DerSimonian-Laird estimator) was used. Heterogeneity among studies was examined by Cochrane Q test. 20 trials involving 1786 subjects were included in this meta-analysis. Based on random effect model, there were significant effects of VDFs on serum 25(OH)D (MD:16.94 nmol/L 95% CI: 13.38, 20.50; p < 0.001, I-2 = 99.0%), BMD (MD: 0.03 gr/cm(2); 95% CI: (0.02, 0.05); p < 0.001, I-2 = 58.8%) and paratormone hormone (PTH; MD:-9.22; 95% CI: (-14.97, -3.46); p = 0.002, I-2 = 98.8%). VDFs may increase serum 25(OH)D and BMD while decrease serum PTH levels. We did not find any beneficial effect of VDFs on BTM.