Vitamin D 'can lower cancer risk'

High doses of vitamin D can reduce the risk of developing some common cancers by as much as 50%, US scientists claim. Researchers reviewed 63 old studies and found that the vitamin could reduce the chances of developing breast, ovarian and colon cancer, and others.

Experts cautiously welcomed the University of California study but warned too much vitamin D could harm the kidneys and liver. The "natural" form of the vitamin, called D3, is normally produced in the skin after exposure to sunlight, but is also obtained from certain foods such as oily fish, butter and meat.

The research, done at the University of California in San Diego, looked at the relationship between blood levels of vitamin D and cancer risk. The papers reviewed, published worldwide between 1966 and 2004, included 30 investigations of colon cancer, 13 of breast cancer, 26 of prostate cancer and seven of ovarian cancer.

Scientists said analysis showed that, for at least some cancers, the vitamin D factor could not be ignored. Taking 1,000 international units (IU) - or 25 micrograms - of the vitamin daily could lower an individual's cancer risk by 50% in colon cancer, and by 30% in breast and ovarian cancer, they said.

The findings have been published in the American Journal of Public Health.

Steve - While we are always wary of meta-analysis studies (because they tend to make gross generalizations), we are well aware how crucial it is to have sufficient vitamin D stores. The cancer prevention connection is not suprising because sufficient vitamin D stores suppress Tumor Necorsis Factor (TNF), which when expressed, is implicated in increased cancer risk.