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Effects of Vitamins C and E on Endothelial Function: Systematic Review & Meta-analysis of randomised controlled trials

Published online by Cambridge University Press:  15 April 2015

Ammar W. Ashor
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK College of Medicine, University of Al-Mustansiriyah, Baghdad, Iraq
Mario Siervo
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK
Jose Lara
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK
Clio Oggioni
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK
Sorena Afshar
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK
John C. Mathers
Affiliation:
Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne, NE4 5PL, UK
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Abstract

Type
Abstract
Copyright
Copyright © The Authors 2015 

Endothelial dysfunction is caused by excessive free radical production and nitric oxide (NO) inadequacy. Endothelial dysfunction is the primary cause of vascular disorders and is related to the progression of clinical complications(Reference Vanhoutte, Shimokawa and Tang1). Human trials examining the effects of antioxidant vitamins on endothelial function (EF) showed inconclusive results(Reference Darko, Dornhorst and Kelly2;Reference Plantinga, Ghiadoni and Magagna3). We undertook as systematic review and meta-analysis of the evidence from randomised controlled trials (RCTs) for effects of supplementation with vitamins C and E on EF.

We searched the Medline, Embase, Scopus and the Cochrane Library databases for studies that met the following criteria: 1) RCTs with adult participants, 2) vitamin C or E administered alone or in combination, 3) studies that quantified EF using forearm blood flow or flow mediated dilation. EF responses across studies were pooled as standardised mean differences and analysed using a random-effects model using STATA 12 (StataCorp. 2011. College Station, TX, USA).

Meta-analysis showed a significant improvement in EF in trials supplementing with vitamins C (SMD: 0·25, 95% CI: 0·02, 0·49, P = 0·043) and E (SMD: 0·48, 95% CI: 0·23, 0·72, P = 0·0001) alone whereas the co-administration of both vitamins was ineffective (SMD: 0·12, 95% CI: −0·18, 0·42, P = 0·428). The effect of vitamin C on EF increased with participant age (β: 0·023, CI: 0·001, 0·05, P = 0·042). There was as significant negative correlation between baseline plasma vitamin E concentration and the EF response to vitamin E (β: −0·03, CI: -0·06, −0·001, P = 0·029). Separate supplementation with vitamins C and E improves EF. Furthermore, subgroup analysis emphasises the importance of careful selection of the population group which may benefit from such supplementation.

References

1.Vanhoutte, PM, Shimokawa, H, Tang, EH et al. (2009). Acta Physiol (Oxf) 196, 193222.Google Scholar
2.Darko, D, Dornhorst, A, Kelly, FJ et al. (2002). Clinical Science 103, 339344.Google Scholar
3.Plantinga, Y, Ghiadoni, L, Magagna, A et al. (2007). American Journal of Hypertension 20, 392397.Google Scholar