title: Effects of supplementation with the fat-soluble vitamins E and D on fasting flow-mediated vasodilation in adults: a meta-analysis of randomized controlled trials.
abstract: The effects of fat-soluble vitamin supplementation on cardiovascular disease (CVD) risk are not clear. Therefore, we performed a meta-analysis to quantify effects of fat-soluble vitamin supplements on fasting flow-mediated vasodilation (FMD) of the brachial artery, a validated marker to assess CVD risk. Randomized placebo-controlled trials (RCTs) were identified by a systematic search till July 2014. Seven RCTs studying the effects of vitamin E supplements (range: 300 to 1800 IU per day) and nine RCTs examining the effects of vitamin D supplements, that involved, respectively, 303 and 658 adults, were included. No studies with carotenoid or vitamin K supplements were found. Vitamin E supplementation increased FMD vs. control by 2.42% (95% CI: 0.46% to 4.37%; p = 0.015). No effects of vitamin D supplementation were found (0.15%; 95% CI: -0.21% to 0.51%; p = 0.41). These effects did not depend on subject characteristics, treatment characteristics or technical aspects of the FMD measurement. However, no dose-response relationship was evident for vitamin E, statistical significance depended on one study, while the levels of supplement were far above recommended intakes. The current meta-analysis, therefore, does not provide unambiguous evidence to support the use of fat-soluble vitamin supplements to improve fasting FMD in adults.
authors.affiliation: Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands. p.joris@maastrichtuniversity.nl.|Top Institute of Food and Nutrition (TIFN), Wageningen 6709 PA, The Netherlands. p.joris@maastrichtuniversity.nl.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Joris
authors.affiliation: Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht 6200 MD, The Netherlands. r.mensink@maastrichtuniversisty.nl.|Top Institute of Food and Nutrition (TIFN), Wageningen 6709 PA, The Netherlands. r.mensink@maastrichtuniversisty.nl.
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Mensink
mesh_terms: D000328:Adult; D002318:Cardiovascular Diseases / Q000517:prevention & control; D019587:Dietary Supplements; D005215:Fasting; D006801:Humans; D014664:Vasodilation / Q000187:drug effects*; D014807:Vitamin D / Q000494:pharmacology*; D014810:Vitamin E / Q000494:pharmacology*; D014815:Vitamins / Q000494:pharmacology*
chemical_list: D014815:Vitamins; D014807:Vitamin D; D014810:Vitamin E