Several previous studies have suggested concern that an overly high intake of vitamin E may lead to possible health risks, including recent meta-analysis that have linked consumption of vitamin E supplements ( at levels of 400 IU or more) with an increased risk of dying.
However, the new review published in the Journal of Lipid Research concludes that biological mechanisms exist to routinely eliminate excess levels of the vitamin, which therefore makes it 'almost impossible' to consume a harmful amount.
"I believe that past studies which have alleged adverse consequences from vitamin E have misinterpreted the data," said Professor Maret Traber from the Linus Pauling Institute at Oregon State University, USA.
"Taking too much vitamin E is not the real concern," Traber said, who is an internationally recognised expert on vitamin E. "Toxic levels of vitamin E in the body simply do not occur."
"Unlike some other fat-soluble vitamins such as vitamins A and D, it's not possible for toxic levels of vitamin E to accumulate in the liver or other tissues."
Traber added that a 'much more important issue' than the potential for damage is the current global deficiency levels of the vitamin - noting that "more than 90% of people in the U.S. have inadequate levels of vitamin E in their diet."
In her review of how vitamin E is metabolised, Traber noted that researchers have found that two major systems in the liver work to control the level of vitamin E in the body - and that these systems routinely excrete excessive amounts.
Very high intakes achieved with supplementation only succeed in doubling the tissue levels of vitamin E, which is not harmful, she said, noting that because of its interaction with vitamin K vitamin E can cause some increase in bleeding. However, no research has found this poses a health risk.
On the other hand, vitamin E performs many critical roles in optimum health, said Traber.
It protects polyunsaturated fatty acids from oxidizing, may help protect other essential lipids, and has been studied for possible value in many degenerative diseases.
In addition she noted that higher than normal intake levels may be needed for some people who have certain health problems, and smoking has also been shown to deplete vitamin E levels.
Traber said she recommends taking a daily multivitamin that has the full RDA of vitamin E, along with consuming a healthy and balanced diet.