Low Vitamin D Levels May Initiate Cancer Development

Low levels of vitamin D may contribute to cancer development, U.S. researchers have found.

"The first event in cancer is loss of communication among cells due to, among other things, low vitamin D and calcium levels," study leader Cedric Garland, an epidemiologist at the Moores Cancer Center at the University of California, San Diego, said in a university news release."Vitamin D may halt the first stage of the cancer process by re-establishing intercellular junctions in malignancies having an intact vitamin D receptor," Garland said.
He noted that appropriate vitamin D levels can be restored and maintained through diet and supplements. More research into the link between vitamin D and cancer is required, but Garland recommended that people get their vitamin D levels tested during annual check-ups.

Laboratory and animal evidence as well as epidemiologic data suggest that vitamin D status could affect cancer risk. Strong biological and mechanistic bases indicate that vitamin D plays a role in the prevention of colon, prostate, and breast cancers. Emerging epidemiologic data suggest that vitamin D has a protective effect against colon cancer, but the data are not as strong for a protective effect against prostate and breast cancer, and are variable for cancers at other sites . Studies do not consistently show a protective effect or no effect, however. One study of Finnish smokers, for example, found that subjects in the highest quintile of baseline vitamin D status have a three-fold higher risk of developing pancreatic cancer. Vitamin D emerged as a protective factor in a prospective, cross-sectional study of 3,121 adults aged ≥50 years (96% men) who underwent a colonoscopy. The study found that 10% had at least one advanced cancerous lesion. Those with the highest vitamin D intakes (>645 IU/day) had a significantly lower risk of these lesions . However, the Women's Health Initiative, in which 36,282 postmenopausal women of various races and ethnicities were randomly assigned to receive 400 IU vitamin D plus 1,000 mg calcium daily or a placebo, found no significant differences between the groups in the incidence of colorectal cancers over 7 years . More recently, a clinical trial focused on bone health in 1,179 postmenopausal women residing in rural Nebraska found that subjects supplemented daily with calcium (1,400-1,500 mg) and vitamin D3 (1,100 IU) had a significantly lower incidence of cancer over 4 years compared to women taking a placebo . The small number of cancers reported (50) precludes generalizing about a protective effect from either or both nutrients or for cancers at different sites.