A research team from the Lawrence Berkeley Laboratory believes it has solved a paradox concerning the human body's need for vitamin E and its ability to function without regular doses.

Lester Packer of the Applied Sciences Division of LBL and a physiology professor at the University of California said last week his studies showed that vitamin E can be recycled by the same enzymes that carry out chemical reactions that enable human cells to utilize oxygen to produce energy."This means that vitamin E is spared," Packer said. "Once you get it into your body, much of it can be conserved."

Packer, along with colleagues John Maguire and David Wilson, said the findings explained the well-known vitamin E paradox: Humans and animals require vitamin E to protect cell membranes against damage from activated forms of oxygen, yet adult humans and animals on a diet devoid of the vitamin do not develop symptoms of deficiency.

The recycling of vitamin E also explains how it can protect cell membranes when it is present in extremely low concentrations, as low as one molecule of vitamin E for every 2,000 to 10,000 lipid, or fat, molecules in a membrane.

Parker cautioned, however, that vitamin E cannot be avoided completely.

"If you deprive animals of vitamin E," he said, "they seem to age faster. In other words, a 14-month-old animal looks like a 36-month-old animal, and not only looks like it but exhibits a lot of molecular markers - DNA-protein crosslinks, accumulation of damaged enzymes, etc. - associated with aging."

That would support the belief - popular but unsubstantiated by scientific research - that vitamin E helps slow the aging process.

There also exists a large body of evidence linking vitamin E supplementation with protection against cancer, arthritis, atherosclerosis, some types of heart disease, cataracts and other medical conditions.

Vitamin E differs from most vitamins in that it is found primarily in plant oils and, consequently, the only way to increase it naturally is to consume more fat. Since high dietary fat intake is known to be unhealthy, vitamin E should be taken separately to achieve recommended doses.