nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
See here for more discussion.

Friday, November 5, 2010

Taking Vitamin E And Risk Of Strokes

For normally healthy people, taking vitamins has never been definitively shown to improve health, with a few exceptions.

A study in the British Medical Journal (Nov 4) combined a number of studies (a meta-analysis of existing studies, not a new experiement) on Vitamin E and hemorrhagic stroke, finding a small increase in risk.

It's important to note that the word "stroke" applies to more than one type of occurence.  The word actually implies just the result, which is a loss of neurologic function, whether paralysis, loss of sensation, or reduced conscisouness...or all of the above.

When you look at what's happening in a stroke, the underlying pathology can be one of several mechanisms.  The most common two are (1) hemorrhagic, and (2) ischemic.  The former is self-explained--there is bleeding, usually from a ruptured or injured blood vessel.  The latter, is due to sudden reduction in blood flow to an area of the brain, commonly from a clot or plaque that has occluded the artery.

This study looked mainly at hemorrhagic strokes.  From the BBC News Health blog (4 Nov), the results were as follows:
The British Medical Journal study found that for every 1,250 people there is the chance of one extra haemorrhagic stroke - bleeding in the brain.  Researchers from France, Germany and the US studied nine previous trials and nearly 119,000 people.  But the level at which vitamin E becomes harmful is still unknown, experts say.
This is not a huge risk, considering that many everyday things we do are riskier, but it's at least a measurable level.

Interestingly, Vitamin E was found to be slightly protective for risk of ischaemic stroke (the more common type).  The research is also mixed on Vitamin E's effect on coronary artery disease;  some studies say it helps, some say it hurts.

For Onion Peelers,
118 765 participants (59 357 randomized to vitamin E and 59 408 to placebo). Vitamin E had no effect on the risk for total stroke (pooled relative risk 0.98 (95% confidence interval 0.91 to 1.05), P=0.53). In contrast, the risk for haemorrhagic stroke was increased (pooled relative risk 1.22 (1.00 to 1.48), P=0.045), while the risk of ischaemic stroke was reduced (pooled relative risk 0.90 (0.82 to 0.99), P=0.02).  There was no association with pre-existing disease, nor could they uncover a dose relationship.

That there was no relationship between how much Vitamin E was consumed and the degree of risk leaves us unsure of how important this finding is.  Also, note that the risk p-value just squeaked by the 0.05 threshold for significance.  I've talked before about this value.  It's arbitary, but we need some kind of line in the sand.  Otherwise, the likelihood that the findings are the result of random chance become too high.

However, the authors agree--and I agree with them--that diet and exercise are better preventive measures for stroke than supplements or vitamins.

A healthy lifestyle, as usual, beats the Magic Potions.

Doc D

No comments:

Post a Comment


What I'm Reading - Updated 3 May

Blog Archive