Numerous studies in the last few years have documented a variety of health benefits provided by vitamin D.
While sun exposure is a good source of vitamin D many people today use sunscreen most of the time when they are outside. Vitamin D deficiency has been found to be fairly common even in warmer climates. For that reason most people will benefit from supplementing with vitamin D. 1000 to 2000 IU per day is usually adequate.
The research reviewed here is related to vitamin D status and prostate cancer (Fang F, et al. 2011). The investigators compared men in the lowest and highest quartile of 25 (OH) vitamin D levels and risk of death from prostate cancer or the development of bone metastases. 25 (OH) vitamin D is the most common form of vitamin D to test for.
The results showed that men in the lowest quartile of vitamin D were more likely to die of their cancer when compared to those in the highest quartile.
You can read more about the benefits of vitamin D.