1.
The Effect of Antioxidant Vitamins on Patients With Diabetes and Albuminuria: A Meta-Analysis of Randomized Controlled Trials.
Chen, J, Wu, J, Kong, D, Yang, C, Yu, H, Pan, Q, Liu, W, Ding, Y, Liu, H
Journal of renal nutrition : the official journal of the Council on Renal Nutrition of the National Kidney Foundation. 2020;(2):101-110
Abstract
OBJECTIVE This study aimed to investigate the effect of antioxidant vitamins, including vitamins E and C, on patients with diabetes and albuminuria by conducting a meta-analysis of randomized controlled trials. DESIGN The PubMed, Embase, CENTRAL (the Cochrane Central Register of Controlled Trials at the Cochrane Library), Web of Science, OVID, and www.clinicaltrials.gov (latest search: December 10, 2018) databases were searched. This study was limited to randomized controlled trials. Patients with diabetes and albuminuria were included regardless of diabetic type, and patients must have received treatment with vitamins C or E. RESULTS Ten studies, representing 445 participants, were identified for analysis. Antioxidant vitamins had significant effects on serum creatinine levels (mean difference = -0.11 mg/dL, 95% confidence interval -0.19 to -0.03, P = .007) and systolic pressure (mean difference = -6.02 mm Hg, 95% confidence interval -9.65 to -2.40, P = .001) with low heterogeneity. Antioxidant vitamins had no effect on albuminuria or proteinuria, diastolic blood pressure, glucose, or lipid metabolism. CONCLUSION This meta-analysis indicated that antioxidant vitamins can benefit kidney function and systolic blood pressure in patients with diabetes and albuminuria. Further studies with larger sample sizes and longer follow-up are needed to completely understand the effect of antioxidant vitamins in these patients.
2.
Effect of Oral Vitamin C Supplementation on High-Altitude Hyperuricemia in Young Men Initially Migrating to High Altitude: A Pilot Study.
Peng, H, Feng, D, Wang, Y, Dong, Z, Chen, Q, Zhang, L, Luo, R, Chen, J, Wang, A, Ma, S
High altitude medicine & biology. 2018;(4):373-381
Abstract
OBJECTIVE Clinical studies have shown that oral vitamin C supplementation can reduce serum uric acid levels in multiple populations and may also improve acute mountain sickness. However, it is unclear whether this protocol can improve high-altitude hyperuricemia. Therefore, we aimed to evaluate the role of vitamin C supplementation on high-altitude hyperuricemia. METHODS A preliminary prospective control study was performed in 2015. Young male army recruits (n = 66), who had recently arrived on the Tibetan Plateau for the first time, were recruited for study I. Subjects were assigned to either the vitamin C group, who took an oral daily dose of 500 mg vitamin C for 1 month, or the blank control group, who had no intervention. The levels of serum uric acid, serum creatinine, and blood urea nitrogen were monitored at baseline and at the end of 1 month. In a second study II in 2016 (n = 120), the effect of 500 mg/d vitamin C on high-altitude hyperuricemia was compared with 75 IU/d of vitamin E. RESULTS In study I, the level of serum uric acid at 1 month was significantly higher than at baseline (436.1 ± 79.3 μmol/L vs. 358.0 ± 79.8 μmol/L, p < 0.001) and the prevalence of hyperuricemia was also significantly higher (63.6% [95% confidence interval, CI: 52.0%-75.2%] vs. 19.7% [95% CI: 10.1%-29.3%], p < 0.001). Both the level of serum uric acid (411.5 ± 74.2 μmol/L vs. 460.8 ± 54.8 μmol/L, p = 0.003) and the prevalence of hyperuricemia (48.5% [95% CI: 31.4%-65.6%] vs. 78.8% [95% CI: 64.9%-92.7%], p = 0.020) were significantly lower in the vitamin C group than in the blank control group. In study II, the levels of serum uric acid and the frequency of hyperuricemia also increased over 1 month and were similar in the vitamin C and the vitamin E groups at both baseline and 1 month (p > 0.05). The change in serum uric acid was positively correlated with both the changes in serum creatinine (r = 0.599, p < 0.001) and blood urea nitrogen (r = 0.207, p = 0.005). CONCLUSIONS These findings indicate that healthy young men develop an increase in serum uric acid within a month of moving from low to high altitude. Oral vitamin C supplementation can safely reduce this increase at a low cost.
3.
Vitamin D status in chronic dialysis patients with depression: a prospective study.
Zhang, J, Zhang, P, Ni, X, Bao, B, Huang, C, Wu, Y, Ni, M, Duan, J, Chen, J
BMC psychiatry. 2014;:125
Abstract
BACKGROUND Depression is the most widely acknowledged psychological problem among end-stage renal disease (ESRD) patients. Depression may be associated with VD deficiency. The aims of this study are to (a) elucidate the prospective association between HsCRP, VD contents and depressive symptoms in the dialyzed population, and (b) find the effect of calcitriol supplementation on depression in dialyzed patients. METHODS In this prospective study, 484 dialysis patients (382 hemodialysis [HD] cases and 102 peritoneal dialysis [PD] cases; aged 18-60 years) from two hospitals in southeast China were included. The depression in these patients was evaluated using the Chinese version of Beck's Depression Inventory (BDI). All subjects answered the BDI-I questionnaire for assessment of depression levels in summer. A cut-off value of 16 was set to include dialysis patients with depression. All patients were divided into two groups depending on the absence (Group 1) or presence (Group 2) of depression. The two groups took 0.5 μg/day 1,25-Dihydroxyvitamin D orally for one year. BDI Scores were recalculated for all patients. Sociodemographic, clinical data, and serum VD contents were also collected. RESULTS A total of 484 participants (247 men [51.0%] and 237 women [49.0%]) were surveyed. Depressive symptoms were found in 213 (44.0%) patients. The baseline serum VD level (VD2 + VD3) was 17.6 ± 7.7 nmol/L. Patients with depressive symptoms have significantly higher serum HsCRP level and significantly lower serum VD level compared with the control group. After one-year follow-up, the supplementation of 0.5 μg/day calcitriol slightly improved the microinflammatory state such as lowering mean serum HsCRP level and improving serum VD level, but not in significantly enhancing the depressive symptoms. CONCLUSIONS Calcitriol supplementation did not significantly enhance the depressive symptoms in our dialyzed population although patients with low levels of serum VD were more depressed. Therefore, more prospective randomized controlled trials are necessary to reveal the exact cause-and-effect relationship between VD status and depressive symptoms or VD status related to some specific subtypes in dialyzed patients.