Daniel Fabricant, Ph.D., vice president, scientific and regulatory affairs for the Natural Products Association, noted the quality of research for a recently published study on vitamin E. The study, "The relationship between dose of vitamin E and suppression of oxidative stress in humans," reported that a dose of 3,200 International Units of vitamin E is needed to reduce oxidative stress in individuals at risk for cardiovascular disease, compared with how previous trials using lower doses failed to show any benefits for the vitamin. Fabricant called the study a “very well done multiple ascending dose study."
In comments reported in the online publication, NutraIngredients.com, Fabricant said "Most dose ranging studies use a disease-free population; the subjects in this group all had polygenic hypercholesterolemia, which is the group that may benefit the most from vitamin E supplementation, thus it is more of a targeted approach in looking at markers (F2-isoprostanes), the dynamics and some basic kinetics (i.e. reduction in plasma concentration), while additional ADME (absorption, distribution, metabolism, and excretion) type data will be helpful in nailing down an optimal dosing range (which should be conducted in a disease free and larger study population (this will be helpful in accounting for gender differences as well)."
"This is a very practical approach to address a large problem with a number of studies on nutrients, where no effect was observed due to the dose being too low. This is very timely considering some of the recent information on intake levels of other nutrients, like vitamin D," he concluded.
The study, out of Vanderbilt University, reported that randomized placebo-controlled trials evaluating the efficacy of vitamin E in preventing cardiovascular events in aggregate have failed to show a beneficial effect. The researchers suspected that the studies had been poorly designed because the trials used a single dose of vitamin E and only looked for end points such as heart attack occurrence. (Free Radical Biology and Medicine (2007), doi:10.1016/ j.freeradbiomed.2007.06.019)