There's more evidence of a link between vitamin D and cancer, and you can probably reduce your cancer risk over time by taking this supplement.
In a study in the American Journal of Preventive Medicine (link below), researchers analyzed data from five studies on vitamin D and colon cancer and found that people with higher levels had a 50 percent lower risk of colon cancer over the years.
Vitamin D is made when sunlight strikes skin, but can be taken as a pill also. In low areas like Buffalo, this is just about the only option for getting vitamin D for most of the year. 1,000 to 2,000 units a day is absolutely safe, and is enough to lower your cancer risk.
Vitamin D levels may explain why many cancers are less frequent in the southeastern US, and more frequent in the Northeast.