Sun, Vitamin D May Cut Cancer Risk

Solar ultraviolet B irradiance is associated with reduced risk of 16 sites of cancer, most likely through production of vitamin D, a U.S. study finds.

The cancers include: six sites of gastrointestinal cancers, three cancers of female sites, three urogenital cancers, two types of lymphomas and 2 upper aerodigestive tract cancers.

The study, published in Anticancer Research, examined age-adjusted mortality-rate data from 49 states plus the District of Columbia for two periods: 1950-69 and 1970-94.

This study provides important additional support for the vitamin D/cancer hypothesis, said William Grant of the University of California, Berkeley. The mechanisms whereby vitamin D reduces the risk of cancer are well known, and include effects on intercellular adhesion, the inhibition of angiogenesis around tumors and the inhibition of metastasis.

Enhancing vitamin D status appears to be the single most important thing that people can do to reduce their risk of cancer, apart from avoiding tobacco and moderation in intake of alcohol, according to study co-author Cedric Garland of the University of California at San Diego School of Medicine.