Vitamin D May Suppress Pancreatic Cancer

Researchers at Northwestern and Harvard Universities have found that consumption of vitamin D tablets cut the risk of pancreatic cancer nearly in half, indicating vitamin D's potential to prevent the disease. The study, led by Halcyon Skinner, Ph.D., at Northwestern University, Evanston, IL, appears in the Sept. issue of Cancer Epidemiology Biomarkers & Prevention.

"In concert with laboratory results suggesting anti-tumor effects of vitamin D, our results point to a possible role for vitamin D in the prevention and possible reduction in mortality of pancreatic cancer. Since no other environmental or dietary factor showed this risk relationship, more study of vitamin D's role is warranted," Skinner said.

This is one of the first known studies to use a large-scale epidemiological survey to examine the relationship between vitamin D and cancer of the pancreas. It examined data from two large, long-term health surveys of health and diet practices, conducted at Harvard University, Boston, and found that taking 400 IU per day of vitamin D (the U.S. RDA), reduced the risk of pancreatic cancer by 43%. Subjects who consumed less than 150 IU per day only had a 22% reduced risk of the disease. Increasing vitamin D consumption above 400 IU per day did not significantly increase the protection.

The study also looked at the association between pancreatic cancer and calcium and retinol (vitamin A). Calcium and retinol intakes showed no association with pancreatic cancer risk, even though retinol reduces vitamin D's ability to influence mineral balances and bone integrity. Thus, researchers believe further research is warranted to determine if vitamin D in the diet, from sources like eggs, liver and fatty fish or fortified dairy products, or production through sun exposure, might be preferable to retinol-containing multivitamin supplements.

"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 Skinner, currently in the Department of Population Health Sciences at the University of Wisconsin School of Medicine and Public Health, Madison. "Vitamin D has shown 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. Few studies have examined this association, and we did observe a reduced risk for pancreatic cancer with higher intake of Vitamin D."

The studies examined were Harvard's Health Professionals Follow-up Study, with 46,771 men aged 40 to 75 years, and Nurses' Health Study, involving 75,427 women aged 38 to 65 years. The studies identified 365 cases of pancreatic cancer, the fourth-leading cause of death from cancer in the United States.