BETHESDA, MARYLAND. The relationship between blood levels of alpha-tocopherol (the most active form of vitamin E) and the risk of lung cancer is not clear. Some studies have found higher levels of alpha-tocopherol protective while other studies have found no such effect. A team of researchers from the National Cancer Institute and the National Public Health Institute in Helsinki, Finland has just released a report that concludes that high alpha-tocopherol levels are indeed protective. The study (ATBC Study) involved 29,102 white, male, Finnish smokers aged 50 to 69 years. The men had blood samples drawn for alpha-tocopherol analysis at entry to the study and were then followed up for a median period of 7.7 years. The study was designed to examine the effects of beta-carotene and vitamin E supplementation on lung cancer incidence.
At the end of the follow-up period 1144 of the study participants had developed lung cancer. A 19 per cent reduction in incidence was observed among participants with the highest baseline blood levels (highest quintile) of alpha-tocopherol as compared to those with the lowest levels. The inverse association was particularly strong among younger men (60 years or younger), among men with less tobacco exposure (less than 40 years of smoking), and possibly among men receiving alpha-tocopherol supplementation.
The researchers conclude that high levels of alpha-tocopherol may inhibit lung cancer
development if present during the early stages of tumour formation. They go on to say
that "While it is tempting, based on the present data, to speculate that the administration
of greater quantities of alpha-tocopherol (i.e. more than 50 mg daily) might have produced
a substantial reduction in lung cancer incidence in the ATBC Study, only future studies,
and controlled trials in particular, can shed light on this question." Editor's Note:
50 mg/day of synthetic alpha-tocopherol as used in the ATBC Study would correspond to
about 25 IU of natural vitamin E, a far lower level than the 200-400 IU/day found to have
beneficial effects in regard to cardiovascular disease.