Can Dietary Intake of Vitamin C-Oriented Foods Reduce the Risk of Osteoporosis, Fracture, and BMD Loss? Systematic Review With Meta-Analyses of Recent Studies

Abstract

Background: Several epidemiological studies have been performed to evaluate the association of dietary intake of vitamin C-oriented foods (DIVCF) with risk of fracture and bone mineral density (BMD) loss, but the results remain controversial. Therefore, we conducted a systematic meta-analysis to assess this correlation. Methods: We searched EmBase, PubMed, Web of Science, and the Chinese database CNKI for relevant articles published up to August 2019. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using the random-or fixed-effects model. Discrepancies were resolved by consultation with a third expert. Results: A total of 13 eligible articles (including 17 studies) with 19,484 subjects were identified for the present meta-analysis. The pooled RR of hip fracture for the highest vs. lowest category was 0.66 (95% CI, 0.47-0.94) for DIVCF, i.e., people with a greater frequency of Vitamin C uptake had a 34% (95% CI, 6%−53%) lower prevalence of hip fracture. In subgroup analyses stratified by study design, gender, and age, the negative associations were statistically significant. Furthermore, the statistical analysis of the association between DIVCF and risk of osteoporosis (RR, 0.66; 95% CI, 0.48-0.92), BMD at the lumbar spine (pooled r, 0.15; 95% CI, 0.09-0.23), and BMD at the femoral neck (pooled r, 0.20; 95% CI, 0.11-0.34) showed beneficial effects of DIVCF. Conclusion: Our meta-analysis indicates that DIVCF is negatively associated with the risk of hip fracture, osteoporosis, and BMD loss, suggesting that DIVCF decreases the risk of hip fracture, osteoporosis, and BMD loss.

Role of Vitamin C in Osteoporosis Development and Treatment—A Literature Review

“…Serum VC concentration has been shown to correlate with low energy fracture risk [52,65] and BMD level [61,65,67], but lack of correlation was reported, too [64,67]. A positive impact of dietary VC intake on BMD may be confirmed by the cumulative result obtained from the meta-analysis in which BMD at the lumbar spine (pooled r = 0.15; 95% CI, 0.09-0.23) and BMD at the femoral neck (pooled r = 0.20; 95% CI, 0.11-0.34; p < 0.05) showed beneficial effects of dietary intake of vitamin C oriented food [12]. Discrepancies between the results obtained may result, among others, from the differences in protocols of the conducted tests and the exclusion criteria used.…”

“…There are currently over 200 different forms available in the literature, the size of which ranges from 5–350 items [ 69 ]. The researchers of the presented study used forms containing 79–220 items [ 12 , 53 , 54 , 56 , 57 , 58 , 61 , 63 , 64 , 66 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ] as well as 24-h dietary recall [ 50 , 51 , 55 , 59 , 65 , 76 ], 3–7 day diet diary [ 52 , 58 , 60 , 67 , 77 ] and other surveys dedicated to their study [ 63 ]. The diversity of the methodology used to assess the average daily dose of vitamin C may cause difficulties in comparing the results obtained.…”

“…Their results indicate a beneficial effect of higher VC intake on the reduction of fracture risk, however the relationship was observed only in men [52,65]. In a meta-analysis prepared by Zeng et al [12] it was concluded that patients with a higher frequency of vitamin C intake had a 34% (95% CI, 6-53%) lower prevalence of hip fracture.…”

“…One plausible explanation is the putative buffering effect of acids derived from vegetables and fruits [8,9]. Moreover, numerous epidemiological studies suggested the importance of micronutrients such as ascorbic acid (vitamin C, VC) in protection against bone loss, not only due to their buffering effects [10][11][12]. Vitamin C is an organic chemical compound from the group of unsaturated polyhydroxy alcohols.…”

Association of Dietary Total Antioxidant Capacity with Bone Mass and Osteoporosis Risk in Korean Women: Analysis of the Korea National Health and Nutrition Examination Survey 2008–2011

“…Antioxidants present in fruits and vegetables have been highlighted as one of the key causes of beneficial outcomes for bone health [ 5 ]. Epidemiological studies have shown that BMD is positively related to the intake of vitamin C [ 38 ], vitamin E [ 8 ], carotenoids [ 6 ], and flavonoids [ 10 , 11 ] in postmenopausal women. Collectively, these observations indicated that the BMD of the femoral neck was strongly affected by the intake of antioxidants, while the BMD of the total hip and lumbar spine was slightly affected in postmenopausal women.…”