MAIN METHODS: Cell mineralization capacity of phytoestrogens was investigated by evaluating calcium, phosphate content and alkaline phosphatase activity. Bone related markers, osteocalcin and osteonectin, responsible in maintaining mineralization were also measured.
KEY FINDINGS: BPA is significantly interfering with bone mineralization in hFOB 1.19 cells. However, the enhanced mineralization efficacy of daidzein and genistein (particularly at a dose of 5 and 40 μg/mL, respectively) was evidenced by increasing calcium and phosphate content, higher ALP activity, compared to the untreated BPA group. The quantitative analyses were confirmed through morphological findings. Osteocalcin and osteonectin levels were increased in phytoestrogens-treated cells. These findings revealed the potential effect of phytoestrogens in reverting the demineralization process due to BPA exposure in hFOB 1.19 cells.
SIGNIFICANCE: We found that osteoblast differentiation and mineralization were maintained following treatment with phytoestrogens under BPA exposure.
OBJECTIVE: This review aims to assess the current evidence of the bone-sparing effects of vitamin C derived from cell, animal and human studies.
RESULTS: Cell studies showed that vitamin C was able to induce osteoblast and osteoclast formation. However, high-dose vitamin C might increase oxidative stress and subsequently lead to cell death. Vitamin C-deficient animals showed impaired bone health due to increased osteoclast formation and decreased bone formation. Vitamin C supplementation was able to prevent bone loss in several animal models of bone loss. Human studies generally showed a positive relationship between vitamin C and bone health, indicated by bone mineral density, fracture probability and bone turnover markers. Some studies suggested that the relationship between vitamin C and bone health could be U-shaped, more prominent in certain subgroups and different between dietary and supplemental form. However, most of the studies were observational, thus could not confirm causality. One clinical trial was performed, but it was not a randomized controlled trial, thus confounding factors could not be excluded.
CONCLUSION: vitamin C may exert beneficial effects on bone, but more rigorous studies and clinical trials should be performed to validate this claim.