New Studies Boost Hopes for Vitamin D as Cancer Weapon


VITAMIN D MAY NOT exactly the miracle vitamin," as a recent Reader's Digest breathlessly hyped it, but evidence of its health benefits does keep making headlines. Now, researchers have found that getting the daily adequate intake of vitamin D (400 IU) may reduce the risk of pancreatic cancer. The new study, in Cancer Epidemiology Biomarkers & Prevention, found a protective effect regardless of whether the vitamin D came from food, supplements or a combination.

"Because there is no effective screening for pancreatic cancer, identifying controllable risk factors for the disease is essential for developing strategies that can prevent cancer," said lead author Halcyon G. Skinner, PhD, currently at the University of Wisconsin School of Medicine and Public Health. "Vitamin D has shown a strong potential for preventing and treating prostate cancer, and areas with greater sunlight exposure have lower incidence and mortality for prostate, breast and colon cancers, leading us to investigate a role for vitamin D in pancreatic cancer risk."

Prevention is particularly important for pancreatic cancer, the US' fourth-leading cause of death from cancer, because it's rarely detected early enough to treat. Some 32,000 new cases are diagnosed annually, and only 5% of patients survive longer than five years.

The epidemiological cohort study analyzed data on 46,771 men ages 40 to 75 from the Health Professionals Follow-up Study and on 75,427 women ages 38 to 65 from the Nurses' Health Study who completed diet questionnaires. Over 16 years of follow-up, there were 365 cases of pancreatic cancer.

Compared with those in the lowest vitamin D-intake group (less than 150 IU daily), those getting 300 to 449 IU daily had 43 % less risk of pancreatic cancer. Risk was also reduced, but not significantly different, for those at even higher vitamin D levels.

FURTHER EVIDENCE of vitamin D's possible anti-cancer benefits comes from a second new study that suggests it may be associated with a slower progression of breast cancer. Researchers at Imperial College of London measured vitamin D levels in blood samples of 279 women with breast cancer. The study found that levels of vitamin D were lower in the 75 women with advanced breast cancer than in the 204 women with early-stage cancer.

Lead author Carlo Palmieri, MD, noted that the researchers don't know whether the low levels of vitamin D are a cause or a consequence of the cancer. But he points out, "There is in vitro, epidemiological and in vivo data to support the view that vitamin D has a role to play in the pathogenesis and progression of breast cancer.

"The next step in this research is to try and understand the potential causes and mechanisms underlying these differences and the precise consequences at a molecular level," Dr. Palmieri says.

TO LEARN MORE: Cancer Epidemiology Biomarkers & Prevention, September 2006; abstract at . Journal of Clinical Pathology online ahead of print, abstract at .

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