Vitamin E and the risk of stroke

Researchers at Harvard Medical School, in Boston, reviewed the evidence.

A stroke is the sudden death of brain cells due to inadequate blood flow. Ischemic stroke is the most common kind of stroke and is caused by an interruption in the flow of blood to the brain (as from a clot blocking a blood vessel). Hemorrhagic stroke is caused by a ruptured blood vessel in the brain.

First, the details.

• 9 studies investigating the effect of vitamin E on stroke were included, totaling 118,765 participants (including vitamin E and placebo).
  • 7 reported data for total stroke.
  • 5 studies each reported on hemorrhagic and ischemic stroke.
• Studies had to have at least 1 year of follow-up.

And, the results.

• Vitamin E had no effect on the risk for total stroke.
• The risk for hemorrhagic stroke was increased 22% — a significant difference.
• The risk of ischemic stroke was reduced 10% — a significant difference.
• In terms of absolute risk, this translates into 1 additional hemorrhagic stroke for every 1250 individuals taking vitamin E.
• In contrast 1 ischemic stroke was prevented for every 476 individuals taking vitamin E.

The bottom line?

The authors concluded, “Given the relatively small risk reduction of ischemic stroke and the generally more severe outcome of hemorrhagic stroke, indiscriminate widespread use of vitamin E should be cautioned against.”

11/30/10 21:07 JR