E-VITAMIININ YLIANNOSTUS VAARALLISTA

[Bb]

Lähettäjä: Soijuv Lähetetty: 11.11.2004 11:36

Sellaisilla henkilöillä jotka käyttävät E-vitamiinia suuria annoksia esim. 2000 IU/pv, saattaa olla yli 20 % normaalia suurempi (yleinen) kuolleisuusriski:


AHA: High-Dose Vitamin E May Increase Mortality Risk

By Charlene Laino

NEW ORLEANS, LA -- November 10, 2004 -- High dosages of vitamin E increase the risk of all-cause mortality, suggest the results of a meta-analysis of 19 randomized, placebo controlled trials.

Edgar R. Miller III, MD, PhD, n associate professor of medicine, Johns Medical Institutions, Baltimore, Maryland, presented the findings here on November 10th at the American Heart Association Scientific Sessions 2004. The results were simultaneously published online in the Annals of Internal Medicine.

The analysis, which pooled data on 135,967 patients, showed a dose-dependent effect between vitamin E supplementation and mortality, he said. "At 400 IUs, the most commonly marketed dose, the risk of dying is about 10% higher than among people who don't take the vitamin."

The increased risk was more than 20% in subjects who took mega-doses, such as the 2000 IU/day used in the Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP) trial and in the Alzheimer's Disease Cooperative Study (ADCS), he said.

While an Institute of Medicine report sets 1000 IU/day as the "upper tolerable limit" for vitamin E, Dr. Miller said that his findings show the upper tolerable limit should be lowered to 400 IUs/day.

For the meta-analysis, the researchers performed a systematic search of the medical literature to identify randomized, placebo controlled trials of vitamin E. Nine of the studies tested vitamin E alone and 10 tested vitamin E in combination with other vitamins. A hierarchical logistic regression model was used to pool study results and to determine dose response effects.

Nine of the 11 trials testing high-dose vitamin E -- 400 IUs per day or more -- showed an increased risk of all-cause mortality, Dr. Miller reported. The pooled all-cause mortality risk difference in these trials was 39 per 10,000 persons (P =.035).

In contrast, low-dose vitamin E was associated with an all-cause mortality risk difference of -16, he said.

Dr. Miller offered several theories about how vitamin E increases mortality risk. Since vitamin E has anticoagulant properties, high doses could lead to an excess of hemorrhagic stroke, he said. Some research suggests that at high doses, vitamin E stops working like an antioxidant, and instead becomes a pro-oxidant. Still other studies suggest that high doses of vitamin E may displace other fat-soluble antioxidants, he said.


Presentation title: " High-Dose Vitamin E Supplementation May Increase All-Cause Mortality: A Dose Response Meta-Analysis of Randomized Trials." Abstract 3833]
http://www.docguide.com/news/content.ns ... r&count=10