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1.
Effect of dietary vitamins C and E on the risk of Parkinson's disease: A meta-analysis.
Chang, MC, Kwak, SG, Kwak, S
Clinical nutrition (Edinburgh, Scotland). 2021;(6):3922-3930
Abstract
BACKGROUND & AIMS A neuroprotective effect of dietary vitamins C and E on Parkinson's disease (PD) has been suggested, however, several human studies have reported controversial results. Therefore, we conducted a meta-analysis on the effect of vitamins C and E on the risk of Parkinson's disease. METHODS A comprehensive literature search was conducted using the PubMed, EMBASE, Cochrane Library, and SCOPUS databases for studies published up to January 23, 2021. We included studies that reported (1) intake of vitamins C and E using validated methods; (2) assessment of odds ratio (OR), relative risk (RR), or hazard ratio (HR); and (3) patients with PD identified by a neurologist, hospital records, or death certificates. The Comprehensive Meta-Analysis Software 2 program was used for statistical analyses of the pooled data. RESULTS A total of 12 studies (four prospective cohort and eight case-control studies) were included in our meta-analysis. No significant risk reduction was observed in the high vitamin C intake group compared to low intake group. On the other hand, the high vitamin E intake group showed a significantly lower risk of development of PD than the low intake group (pooled OR = 0.799. 95% CI = 0.721 to 0.885). CONCLUSIONS We conclude that vitamin E might have a protective effect against PD, while vitamin C does not seem to have such an effect. However, the exact mechanism of the transport and regulation of vitamin E in the CNS remains elusive, and further studies would be necessary in this field.
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2.
Can vitamin E supplementation affect obesity indices? A systematic review and meta-analysis of twenty-four randomized controlled trials.
Emami, MR, Jamshidi, S, Zarezadeh, M, Khorshidi, M, Olang, B, Sajadi Hezaveh, Z, Sohouli, M, Aryaeian, N
Clinical nutrition (Edinburgh, Scotland). 2021;(5):3201-3209
Abstract
BACKGROUND Several mechanisms have been proposed for the effect of vitamin E on weight loss. Yet various interventional studies with wide ranges of doses and durations have reported contradictory results. METHODS Cochrane Library, PubMed, Scopus, and Embase databases were searched up to December 2020. Meta-analysis was performed using random-effect method. Effect size was presented as weighted mean difference (WMD) and 95% confidence interval (CI). Heterogeneity was evaluated using the I2 index. In order to identification of potential sources of heterogeneity, predefined subgroup and meta regression analyses was conducted. RESULTS A total of 24 studies with 33 data sets were included. There was no significant effect of vitamin E on weight (WMD: 0.15, 95% CI: -1.35 to 1.65, P = 0.847), body mass index (BMI) (WMD = 0.04, 95% CI: -0.29 to 0.37, P = 0.815), and waist circumference (WC) (WMD = -0.19 kg, 95% CI: -2.06 to 1.68, P = 0.842), respectively. However, subgroup analysis revealed that vitamin E supplementation in studies conducted on participants with normal BMI (18.5-24.9) had increasing impact on BMI (P = 0.047). CONCLUSION There was no significant effect of vitamin E supplementation on weight, BMI and WC. However, vitamin E supplementation might be associated with increasing BMI in people with normal BMI (18.5-24.9).
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3.
Beneficial Effects of Vitamin E Supplementation on Endothelial Dysfunction, Inflammation, and Oxidative Stress Biomarkers in Patients Receiving Hemodialysis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
Nguyen, TTU, Yeom, JH, Kim, W
International journal of molecular sciences. 2021;(21)
Abstract
Inflammation and oxidative stress are closely related to cardiovascular complications and atherosclerosis, and have the potential to lead to an increase in death in patients receiving hemodialysis. Vitamin E has antioxidant and anti-inflammatory properties. We conducted a systematic review and meta-analysis to assess the effects of vitamin E supplementation on endothelial dysfunction, inflammation, and oxidative stress biomarkers in adult patients receiving hemodialysis. We searched the MEDLINE, EMBASE, Web of Science, and Cochrane Library databases and identified randomized controlled trials of adult patients receiving hemodialysis until 30 August 2021. A total of 11 trials with 491 randomized patients were included. The pooled data indicated that vitamin E supplementation significantly decreased intercellular adhesion molecule-1 [standardized mean difference (SMD): -1.35; 95% confidence interval (CI): -2.57, -0.13; p = 0.03, I2 = 89%], vascular cell adhesion molecule-1 (SMD: -1.08; 95% CI: -2.05, -0.11; p = 0.03, I2 = 81%), C-reactive protein (SMD: -0.41; 95% CI: -0.75, -0.07; p = 0.02, I2 = 64%), and malondialdehyde (SMD: -0.76; 95% CI: -1.26, -0.25; p = 0.003, I2 = 77%) levels, but not interleukin-6 levels compared to those in the control group. Our results suggest that vitamin E supplementation may help alleviate oxidative stress and both vascular and systemic inflammation in patients receiving hemodialysis.
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4.
Systematic review with meta-analysis: The effect of vitamin E supplementation in adult patients with non-alcoholic fatty liver disease.
Vadarlis, A, Antza, C, Bakaloudi, DR, Doundoulakis, I, Kalopitas, G, Samara, M, Dardavessis, T, Maris, T, Chourdakis, M
Journal of gastroenterology and hepatology. 2021;(2):311-319
Abstract
BACKGROUND AND AIM Νon-alcoholic fatty liver disease (NAFLD) is estimated to be the most common cause of end-stage liver disease in the next years. Vitamin E has shown beneficial effects as a possible "scavenger" of oxidative stress products, which play a major role in pathogenesis of the disease. The purpose of the present meta-analysis is to investigate the effects of vitamin E supplementation in biochemical and histological parameters in adult patients with NAFLD. METHODS Literature search was performed in major electronic databases (MEDLINE, CENTRAL, and Embase) up to June 2020 for randomized clinical trials, which examined vitamin E versus placebo treatment in adults with NAFLD. Changes in liver enzymes were considered as primary outcomes while changes in histological, biochemical, and metabolic parameters as secondary. Quality of evidence was assessed through risk of bias according to the Cochrane risk of bias tool. RESULTS Eight studies were included in qualitative analysis and seven in quantitative analysis. Vitamin E reduced the values of liver enzymes compared with placebo (-7.37 IU/L, 95% confidence interval: -10.11 to -4.64 for alanine aminotransferase, and -5.71 IU/L, 95% confidence interval: -9.49 to -1.93 for aspartate aminotransferase). Additionally, vitamin E improved statistically significantly liver pathology in every individual histological parameter as well as low-density lipoprotein cholesterol, fasting blood glucose, and serum leptin values. CONCLUSIONS Vitamin E can improve biochemical and histological characteristics of NAFLD patients, especially of non-alcoholic steatohepatitis patients. The results indicate that vitamin E could be a promising choice and be considered as a treatment option in patients with NAFLD.
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5.
Vitamin E-Enhanced Liners in Primary Total Hip Arthroplasty: A Systematic Review and Meta-Analysis.
Cheng, QY, Zhang, BF, Wen, PF, Wang, J, Hao, LJ, Wang, T, Cheng, HG, Wang, YK, Guo, JB, Zhang, YM
BioMed research international. 2021;:3236679
Abstract
OBJECTIVE Adding vitamin E to highly cross-linked polyethylene liners is frequently performed in clinical practice, aiming at reducing liner wear, increasing liner survival, and delaying revision surgery. This study is aimed at evaluating the revision rate, total femoral head penetration, and postoperative clinical function of highly cross-linked polyethylene liners with and without vitamin E in total hip arthroplasty. METHODS We conducted a systematic literature search to identify the use of highly cross-linked vitamin E liners compared to other liners in patients who received total hip arthroplasty (THA) before April 2021. The study quality assessment and data collection were conducted by two independent reviewers. Studies were artificially grouped, and vitamin E-enhanced liners (VE-PE) were compared with vitamin E-free liners (non-VE-PE). Analyses were executed using Review Manager version 5.4.1. RESULTS From the preliminary screening of 568 studies, fourteen studies met the research criteria. Compared to non-VE-PE, using VE-PE reduced the all-cause revision rate (odds ratio = 0.54; 95% confidence interval (CI) 0.40, 0.73; P < 0.0001). The total femoral head penetration of the VE-PE was lower than that of the non-VE-PE (mean difference = -0.10; 95% CI -0.17, -0.03; P = 0.007). However, there was no difference in clinical function, including the Harris Hip Score and EuroQol Five-Dimension Questionnaire scores. CONCLUSION Compared to the liners without vitamin E, the addition of vitamin E to liners could reduce the all-cause revision rate by approximately 46% in the short-term follow-up. In addition, even though addition of vitamin E could also slow down femoral head penetration, there is no contribution to clinical function.
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6.
The effectiveness of coenzyme Q10, vitamin E, inositols, and vitamin D in improving the endocrine and metabolic profiles in women with polycystic ovary syndrome: a network Meta-analysis.
Zhang, J, Xing, C, Zhao, H, He, B
Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology. 2021;(12):1063-1071
Abstract
OBJECTIVE This research evaluated the efficacy of oral nutritional agents including CoQ10, vitamin E, inositols and vitamin D on androgen-associated hormones, glycolipid metabolism and body weight in women with PCOS. METHOD A multi-database search was performed from inception to December 2020. Using multi-variate random effects method, a NMA was conducted by synthesizing data pooled from RCTs. It was registered with PROSPERO (registration number CRD42021230292). RESULTS Twenty-three RCTs and 1291 participants were included. Based on NMA, CoQ10, vitamin E, CoQ10 combined with vitamin E, and inositols were successful in decreasing TT as compared with PA; vitamin E was superior to other agents. Vitamin E and inositols were successful in increasing SHBG levels; inositols were stronger than vitamin E. CoQ10 alone or combined with vitamin E, and inositols were successful in decreasing HOMA-IR. Inositols had the best results among included nutraceuticals to ameliorate HOMA-IR, FBG, FINS, TG, TC, and LDL-C and correlated to improvements in BMI. There was no significant difference between the CoQ10 or vitamin E group and the PA group in ameliorating lipid metabolism, and vitamin D had no positive effects in ameliorating hyperandrogenism, BMI, glycolipid metabolism profiles compared with PA. CONCLUSION For women with PCOS, inositols supplementation have some certain advantages in increasing SHBG and improving glycolipid metabolism when compared with nutraceuticals like CoQ10, vitamin E, vitamin D. Besides, vitamin E may be a better option in reducing TT and increasing SHBG. CoQ10 alone or combined with vitamin E can be helpful in decreasing HOMA-IR as well.
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7.
Effects of vitamin E on stroke: a systematic review with meta-analysis and trial sequential analysis.
Loh, HC, Lim, R, Lee, KW, Ooi, CY, Chuan, DR, Looi, I, Kah Hay, Y, Abdul Karim Khan, N
Stroke and vascular neurology. 2021;(1):109-120
Abstract
There are several previous studies on the association of vitamin E with prevention of stroke but the findings remain controversial. We have conducted a systematic review, meta-analysis together with trial sequential analysis of randomised controlled trials to evaluate the effect of vitamin E supplementation versus placebo/no vitamin E on the risk reduction of total, fatal, non-fatal, haemorrhagic and ischaemic stroke. Relevant studies were identified by searching online databases through Medline, PubMed and Cochrane Central Register of Controlled Trials. A total of 18 studies with 148 016 participants were included in the analysis. There was no significant difference in the prevention of total stroke (RR (relative risk)=0.98, 95% CI 0.92-1.04, p=0.57), fatal stroke (RR=0.96, 95% CI 0.77-1.20, p=0.73) and non-fatal stroke (RR=0.96, 95% CI 0.88-1.05, p=0.35). Subgroup analyses were performed under each category (total stroke, fatal stroke and non-fatal stroke) and included the following subgroups (types of prevention, source and dosage of vitamin E and vitamin E alone vs control). The findings in all subgroup analyses were statistically insignificant. In stroke subtypes analysis, vitamin E showed significant risk reduction in ischaemic stroke (RR=0.92, 95% CI 0.85-0.99, p=0.04) but not in haemorrhagic stroke (RR=1.17, 95% CI 0.98-1.39, p=0.08). However, the trial sequential analysis demonstrated that more studies were needed to control random errors. Limitations of this study include the following: trials design may not have provided sufficient power to detect a change in stroke outcomes, participants may have had different lifestyles or health issues, there were a limited number of studies available for subgroup analysis, studies were mostly done in developed countries, and the total sample size for all included studies was insufficient to obtain a meaningful result from meta-analysis. In conclusion, there is still a lack of statistically significant evidence of the effects of vitamin E on the risk reduction of stroke. Nevertheless, vitamin E may offer some benefits in the prevention of ischaemic stroke and additional well-designed randomised controlled trials are needed to arrive at a definitive finding. PROSPERO registration number: CRD42020167827.
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8.
Effects of vitamin E supplementation on the risk and progression of AD: a systematic review and meta-analysis.
Wang, W, Li, J, Zhang, H, Wang, X, Zhang, X
Nutritional neuroscience. 2021;(1):13-22
Abstract
Objective: The association between vitamin E supplementation and Alzheimer's disease (AD) was controversial because of conflicting data in the literature. This study was designed to systematically evaluate evidence about the efficacy of vitamin E supplementation not only on the risk but also on the progression of AD. Design: Five electronic databases were searched for studies published up to June 2017. Articles reporting vitamin E supplementation and AD were included, and the random-effect model was performed for the meta-analysis about the relationship between vitamin E supplementation and AD. Results: Five cohort studies and three randomized controlled trial (RCT) studies (total n = 14,262) involving 1313 cases about vitamin E effects on the risk of AD and 244 cases about effects on progression of AD. The pooled RR for vitamin E supplemental and risk of AD was 0.81 [95% CI: 0.50-1.33, I 2 = 69.2%]. Suitable data could not be extracted to do meta-analysis as there was no unified standard of outcome measure for studies on AD progression. We carefully analyzed and evaluated the authenticity and accuracy of every single trial, while reliable evidence could not be obtained. Conclusions: From what we do, neither the synthetic data on risk of AD nor the critical review on progression of AD could provide enough evidence on our research. Thus, we cannot draw a specific conclusion on the association or correlation between Vitamin E and AD.
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9.
The effect of vitamin E supplementation on selected inflammatory biomarkers in adults: a systematic review and meta-analysis of randomized clinical trials.
Asbaghi, O, Sadeghian, M, Nazarian, B, Sarreshtedari, M, Mozaffari-Khosravi, H, Maleki, V, Alizadeh, M, Shokri, A, Sadeghi, O
Scientific reports. 2020;(1):17234
Abstract
The previous meta-analysis of clinical trials revealed a beneficial effect of vitamin E supplementation on serum C-reactive protein (CRP) concentrations; however, it is unknown whether this vitamin has the same influence on other inflammatory biomarkers. Also, several clinical trials have been published since the release of earlier meta-analysis. Therefore, we aimed to conduct a comprehensive meta-analysis to summarize current evidence on the effects of vitamin E supplementation on inflammatory biomarkers in adults. We searched the online databases using relevant keywords up to November 2019. Randomized clinical trials (RCTs) investigating the effect of vitamin E, compared with the placebo, on serum concentrations of inflammatory cytokines were included. Overall, we included 33 trials with a total sample size of 2102 individuals, aged from 20 to 70 years. Based on 36 effect sizes from 26 RCTs on serum concentrations of CRP, we found a significant reduction following supplementation with vitamin E (- 0.52, 95% CI - 0.80, - 0.23 mg/L, P < 0.001). Although the overall effect of vitamin E supplementation on serum concentrations of interleukin-6 (IL-6) was not significant, a significant reduction in this cytokine was seen in studies that used α-tocopherol and those trials that included patients with disorders related to insulin resistance. Moreover, we found a significant reducing effect of vitamin E supplementation on tumor necrosis factor-α (TNF-α) concentrations at high dosages of vitamin E; such that based on dose-response analysis, serum TNF-α concentrations were reduced significantly at the dosages of ≥ 700 mg/day vitamin E (Pnon-linearity = 0.001). Considering different chemical forms of vitamin E, α-tocopherol, unlike other forms, had a reducing effect on serum levels of CRP and IL-6. In conclusion, our findings revealed a beneficial effect of vitamin E supplementation, particularly in the form of α-tocopherol, on subclinical inflammation in adults. Future high-quality RCTs should be conducted to translate this anti-inflammatory effect of vitamin E to the clinical setting.
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10.
Effect of omega-3 fatty acid plus vitamin E Co-Supplementation on oxidative stress parameters: A systematic review and meta-analysis.
Sepidarkish, M, Akbari-Fakhrabadi, M, Daneshzad, E, Yavari, M, Rezaeinejad, M, Morvaridzadeh, M, Heshmati, J
Clinical nutrition (Edinburgh, Scotland). 2020;(4):1019-1025
Abstract
BACKGROUND & AIMS The impact of combined omega-3 FAs and vitamin E supplementation on oxidative stress (OS) has been evaluated in several studies. However the results are inconsistent. Therefore, we performed a systematic review and meta-analysis to assess the role of omega-3 FAplus vitamin E on anti-oxidant and OS parameters. METHODS We searched five databases (PubMed, Embase, Web of Sciences, Scopus and the Cochrane Central Register of Controlled Trials) from inception until March 15th 2018 for RCT covering OS parameters combined with omega-3 FAs and vitamin E. The effect of omega-3 FAs plus vitamin E combination on OS factors was determined as the standardized mean difference (SMD) calculated according to DerSimonian and Laird for the random effects model. RESULTS Nine articles were included in our analyses, significant improvements were observed in trials supplementing with omega-3 FAs plus vitamin E vs placebo for total antioxidant capacity (TAC) (SMD=0.63, 95%CI: 0.31 to 0.95, P<0.001) and nitric oxide (NO) (SMD=0.55, 95%CI: 0.23 to 0.87, P<0.001). Significant reduction was observed for malondialdehyde (MDA) (SMD: -0.48, 95%CI: -0.68 to -0.28, P<0.001). However, the results of meta-analysis did not show a significant difference in levels of glutathione (GSH) (SMD=0.34, 95%CI: -0.07 to 0.75, P=0.10), superoxide dismutase (SOD) activity (SMD: 0.07, 95% CI: -0.58 to 0.73, P=0.82) and Catalase (CAT) activity (SMD: 0.74, 95% CI: -0.30 to 1.79, P=0.16). CONCLUSION Co-supplementation with omega-3 FAs and vitamin E increases the levels of NO and TAC, while MDA levels decrease compared to placebo. However, the results showed no significant alterations on GSH concentrations, CAT, and SOD activities.