Vitamin D doesn't cut prostate cancer risk

By Will Dunham

WASHINGTON (Reuters) - Vitamin D -- the so-called sunshine vitamin -- does not appear to cut a man's risk of getting prostate cancer, researchers said on Tuesday.

Previous studies have found protective effects from higher vitamin D levels for certain cancer types including colon and breast cancer, as well as other ailments.

U.S. National Cancer Institute researchers set out to see if vitamin D might protect against prostate cancer, the second most frequently diagnosed cancer in men worldwide. They tracked vitamin D concentrations in the blood of 749 men diagnosed with prostate cancer and 781 men who did not have the disease.

They found no association between higher levels of the vitamin and a reduced prostate cancer risk. The findings hinted at a possible increased risk for aggressive prostate cancer in men with higher blood concentration of vitamin D, but this link was not statistically significant, the researchers said.

"In our study, we didn't see any protective effect of vitamin D in relation to prostate cancer risk," Jiyoung Ahn of the U.S. National Cancer Institute, one of the researchers, said in a telephone interview.

Levels of vitamin D were measured in a blood sample provided by the men when they entered the study. Those with prostate cancer were diagnosed one to eight years after the blood samples were given, the researchers said.

Ahn, whose study was published in the Journal of the National Cancer Institute, said previous research had shown that high doses of vitamin D inhibited the growth of human prostate cancer cells in a laboratory dish.

The body makes vitamin D when skin is exposed to sunlight, thus earning its nickname the sunshine vitamin. It is found in fatty fish such as salmon and milk commonly is fortified with it.