Vitamin E Supplements and Stroke

Perhaps the confusion about this relationship has been resolved.  There’s been some information reporting that Vitamin E supplements have no effect on overall stroke incidence.  However, when stroke type is examined, the supplements had a differential effect on the incidence of ischemic stroke (the commonest kind) and hemorrhagic stroke (the more lethal kind), according to a British Medical Journal meta-analysis.

Boston US researchers searched the medical literature for studies where vitamin E supplements had been compared with placebo in assessing a protective effect on stroke.  Total stroke, ischemic stroke, and hemorrhagic stroke cases were included.  They found 9 clinical studies that included some 118,000 patients who'd been randomized to take vitamin E or placebo, and were followed for more than a year.

There was no evidence that the rates of stroke overall differed between the groups.  However, when the type of stroke was examined, ischemic strokes were significantly fewer among the vitamin recipients (by 10%), while hemorrhagic strokes were significantly increased (by 22%).

Vitamin E over-dosage is a cause for hemorrhage – the vitamin interferes with the vitamin-K dependent clotting factor.  So this may well be the reason behind the increase in hemorrhagic strokes.  The risk of a hemorrhagic stroke should be set against the (smaller) benefit of decreased ischemic strokes, based on this study’s analysis.  The researchers conclude that that "indiscriminate widespread use of vitamin E should be cautioned against."  This makes sense, as vitamin E has not been shown to be particularly effective in several conditions.  If you must take it, keep the dose within bounds.