Previous vitamin E trials ‘fatally flawed’

Washington, September 23: As against the findings of all previous studies on vitamin E, a new research has now suggested that the levels of the micronutrient that have been commonly used in clinical trials to reduce oxidative stress so far have been far lower than what they actually should be.

Published in Free Radical Biology and Medicine, the study suggests that in order to reduce oxidative stress, the levels of vitamin E—as measured by accepted biomarkers of lipid peroxidation—should be about 1,600 to 3,200 I.U. daily, which is four to eight times higher than the 100 to 400 I.U. a day levels that have been used in almost all past clinical trials.

Balz Frei, professor and director of the Linus Pauling Institute at Oregon State University, has co-authored the new commentary along with Jeffrey Blumberg of the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.

According to Frei, the new findings may help explain the inconsistent results of many vitamin E trials for its value in preventing or treating cardiovascular disease.

“The methodology used in almost all past clinical trials of vitamin E has been fatally flawed. These trials supposedly addressed the hypothesis that reducing oxidative stress could reduce cardiovascular disease. But oxidative stress was never measured in these trials, and therefore we don’t know whether it was actually reduced or not. The hypothesis was never really tested,” said Frei, one of the world’s leading experts on antioxidants and disease.

Although the researchers are not recommending that people should routinely take such high levels of vitamin E, they stress that scientists should seriously consider using much higher vitamin E supplement levels while carrying out controlled clinical trials.

“What’s now clear is that the amount of vitamin E than can conclusively be shown to reduce oxidative stress is higher than we realized. And almost none of the studies done with vitamin E actually measured the beginning level or reduction of oxidative stress,” Frei said.

He says where a clinical trial seeks to learn the value of reducing oxidative stress, scientists 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, he adds.

“A pill count simply isn’t enough to determine the value of vitamin E. We need to select people for trials properly, make sure they are taking the right form of the vitamin, at the right levels and at the right time, and then verify the metabolic results with laboratory testing,” Frei said.

“Only when we do these studies right will we answer questions about the value of vitamin E in addressing cardiovascular disease. So far we’ve been flying blind,” he said. (With Inputs from ANI)