Vitamin E Pills May Block Another Key Vitamin
People who take popular Vitamin E supplements may actually be depleting their body of another form of the vitamin that performs unique and much-needed chemical tasks, scientists say.
New experiments suggest that this uncommon form of Vitamin E found in the body, known as gamma-tocopherol, removes several toxic chemicals that are not addressed by other so-called anti-oxidants.
Scientists who performed the experiments say the results raise questions about the wisdom of taking large doses of Vitamin E. Others said the evidence of benefit from taking several hundred international units of Vitamin E per day is too strong to be shaken by a single experiment.
Gamma-tocopherol is a form of Vitamin E that is not found in popular dietary supplements, which contain a close chemical cousin, alpha-tocopherol.
Nutrition experts have known for a long time that large doses of alpha-tocopherol cause the concentration of gamma-tocopherol to go down by as much as twentyfold. The reason for this is not clear, but may happen because alpha-tocopherol displaces gamma-tocopherol in some vitamin-recycling process.
In research described in today’s edition of the Proceedings of the National Academy of Sciences, biochemists from the University of California at Berkeley and Australia’s University of New South Wales found that in laboratory cultures, gamma-tocopherol inhibited several harmful substances that do not appear to be affected by alpha-tocopherol or any other antioxidant.
“I don’t want to scare people, because this is only a short-term study,” said Stephan Christen, one of the Berkeley scientists, “but I would be careful not to use very high doses of Vitamin E, at least until a supplement that contains gamma-tocopherol is available.”
“This is an interesting experiment, and it shows we need to do more studies,” said Jeffrey Blumberg, professor of nutrition at Tufts University in Boston. “But I don’t want people to react to this by saying, ‘Oh my goodness, I shouldn’t take Vitamin E supplements.’
“The evidence of benefit from taking Vitamin E is just too strong.”