Getting your daily dose of the "sunshine vitamin" may greatly reduce your risk of pancreatic cancer, according to recent study results. Researchers at Northwestern and Harvard universities found that taking just 300 IU/day of vitamin D may cut in half one's risk of pancreatic cancer (Cancer Epidemiology Biomarkers & Prevention, 2006, vol. 15, no. 9).

Researchers analyzed masses of data—from more than 46,000 men (ages 40 to 75) and more than 75,000 women (ages 38 to 65). The men had participated in the Health Professionals Follow-up Study; the women in the Nurses' Health Study.

Scientists identified 365 cases of pancreatic cancer in the group. People who got at least 300 IU daily of vitamin D (through diet, supplements, or both) had a 43 percent lower risk of pancreatic cancer than those who consumed less than 150 IU daily. Subjects in the middle group, who took 150 - 299 IU/day, had a 22 percent reduced risk.

Current Adequate Intake (AI) levels of vitamin D, established by the Institute of Medicine of the National Academy of Sciences, are 200 IU/day for both men and women ages 19 to 50. From ages 51 to 70, the level rises to 400 IU/day. Vitamin D is naturally synthesized in the skin from exposure to sunlight. It also can be found in fortified cereals and dairy products, fatty fish, liver, and eggs.

The American Cancer Society predicts that this year, nearly 34,000 cases of pancreatic cancer will be diagnosed and 32,000 people will die of the disease. Lead researcher Halycon Skinner, PhD, notes that more studies will be needed to confirm the relationship between vitamin D and pancreatic cancer. Still, he says, "Our study joins several others, which have already shown a protective effect of vitamin D against prostate, breast, and colon cancer."