title: Effect of vitamin E supplementation on serum C-reactive protein level: a meta-analysis of randomized controlled trials.
abstract: C-reactive protein (CRP), a marker of chronic inflammation, has a major role in the etiology of chronic disease. Vitamin E may have anti-inflammatory effects. However, there is no consensus on the effects of vitamin E supplementation on CRP levels in clinical trials. The aim of this study was to systematically review randomized controlled trials (RCTs) that report on the effects of vitamin E supplementation (α- and γ-tocopherols) on CRP levels. A systematic search of RCTs was conducted on Medline and EMBASE through PubMed, Scopus, Ovid and Science Direct, and completed by a manual review of the literature up to May 2014. Pooled effects were estimated by using random-effects models and heterogeneity was assessed by Cochran's Q and I(2) tests. Subgroup analyses and meta-regression analyses were also performed according to intervention duration, dose of supplementation and baseline level of CRP. Of 4734 potentially relevant studies, only 12 trials met the inclusion criteria with 246 participants in the intervention arms and 249 participants in control arms. Pooled analysis showed a significant reduction in CRP levels of 0.62 mg/l (95% confidence interval = -0.92, -0.31; P < 0.001) in vitamin E-treated individuals, with the evidence of heterogeneity across studies. This significant effect was maintained in all subgroups, although the univariate meta-regression analysis showed that the vitamin E supplementation dose, baseline level of CRP and duration of intervention were not the sources of the observed heterogeneity. The results of this meta-analysis suggest that supplementation with vitamin E in the form of either α-tocopherol or γ-tocopherol would reduce serum CRP levels.
authors: Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors: S
authors: S
authors: Saboori
authors: Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors: S
authors: S
authors: Shab-Bidar
authors: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China and Institute of Biological and Environmental Sciences, University of Aberdeen, Scotland, UK.
authors: J R
authors: JR
authors: Speakman
authors: Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors: E
authors: E
authors: Yousefi Rad
authors: Department of Clinical Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
authors: K
authors: K
authors: Djafarian
mesh_terms: D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D019587:Dietary Supplements; D006801:Humans; D007249:Inflammation / Q000188:drug therapy; D016032:Randomized Controlled Trials as Topic; D014815:Vitamins / Q000494:pharmacology*; D024502:alpha-Tocopherol / Q000494:pharmacology*; D024504:gamma-Tocopherol / Q000494:pharmacology*
chemical_list: D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D014815:Vitamins; D024504:gamma-Tocopherol; D002097:C-Reactive Protein; D024502:alpha-Tocopherol