Vitamin E trials 'fatally flawed'(der using much higher vitamin E suppleme...)
der using much higher vitamin E supplement levels in their studies.
In lab, animal or human studies, theres evidence that vitamin E can reduce oxidative stress, inhibit formation of atherosclerotic lesions, slow aortic thickening, lower inflammation, and reduce platelet adhesion. Some human studies using lower levels of vitamin E supplements, such as 100 to 400 I.U. a day, have shown benefits in reducing cardiovascular disease risk, and others have not. An underlying assumption was that these levels were more than adequate to reduce oxidative stress, since they far exceeded the recommended dietary allowance or RDA for the vitamin, a level adequate to prevent deficiency disease.
Whats now clear is that the amount of vitamin E than can conclusively be shown to reduce oxidative stress is higher than we realized, Frei said. And almost none of the studies done with vitamin E actually measured the beginning level or reduction of oxidative stress.
Proper studies of vitamin E, researchers say, must be done carefully and take into account the newest findings about this micronutrient. Its now known that natural forms of the vitamin are far more readily absorbed than synthetic types. Its also been discovered that supplements taken without a fat-containing meal are largely useless, because in the absence of dietary fat vitamin E is not absorbed.
Some clinical trials may wish to study the long term effect of vitamins on healthy individuals. But if a clinical trial seeks to learn the value of reducing oxidative stress, they should select patients in advance for those who have high, measurable oxidative stress often people who are older or have a range of heart disease risk factors, such as obesity, poor diet, hypertension or other problems. Cognizance should also be taken of people with health issues that may further increase their vitamin needs, such as smokers.
A pill count simply isnt enough to determine the value of vitamin E, Fre
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| Contact: Balz Frei balz.frei@oregonstate.edu 541-737-5078 Oregon State University Source:Eurekalert |
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