Vitamin E supplementation (alone or with other antioxidants) and stroke: a meta-analysis.

Abstract

A previous study showed that vitamin E is effective in reducing the incidence of myocardial infarction only when it is taken in the absence of other antioxidants. It is unclear if it also reduces the incidence of stroke. The aim of this meta-analysis is to compare the effect of vitamin E supplementation alone or combined with other antioxidants on the incidence of stroke. A search was performed in the following databases: PubMed, ISI Web of Science, SCOPUS, and Cochrane Library. Sixteen randomized controlled trials were selected to evaluate the effect of vitamin E supplementation on stroke. The range of vitamin E doses used was 33-800 IU. The follow-up period ranged from 6 months to 9.4 years. Compared with controls, when vitamin E was given alone it did not reduce the incidence of ischemic and hemorrhagic stroke. Conversely, compared with controls, supplementation of vitamin E with other antioxidants reduced ischemic stroke (random effects, RR: 0.91; 95% CI: 0.84-0.99; P = 0.02) but with a significant increase in hemorrhagic stroke (random effects, RR: 1.22; 95% CI: 1.0-1.48; P = 0.04). Supplementation with vitamin E alone is not associated with stroke reduction. Instead, supplementation of vitamin E with other antioxidants reduces the incidence of ischemic stroke but increases the risk of hemorrhagic stroke, cancelling any beneficial effect derived. Thus, vitamin E is not recommended in stroke prevention. PROSPERO registration no. CRD42022258259.