Narrator: This is Science Today. An adequate amount of vitamin D absorbed by sunlight, diet and supplementation can significantly reduce annual worldwide cases of breast and colorectal cancers. This, according to a new study co-led by Dr. Cedric Garland, a cancer prevention specialist at the University of California, San Diego's Moores Cancer Center.
Garland: We showed that there was a dose response relationship and that the more vitamin D, the less the risk of breast cancer and of colon cancer. We actually were able to plot a curve that showed that.
Narrator: The research, based on decades of prior studies, found that of the 600,000 worldwide cases of colorectal and breast cancer each year, two-thirds of colorectal cancers would be prevented by 2,000 International Units per day of vitamin D and 5,000 International Units per day would prevent about half the cases of breast cancer.
Garland: The risks and benefits of taking 5,000 International Units a day are still being considered now, although recent reviews suggest that intake is certainly safe for adults.
Narrator: For Science Today, I'm Larissa Branin.