Two new meta-analysis studies (which combine data from multiple reports) have found even more evidence that vitamin D is an important cancer-fighting tool. The first study examined nearly 1,800 records and found that:
The second study, which looked at nearly 1,500 people, found similar results. Raising vitamin D levels (serum level of 25-hydroxyvitamin D) to 34 ng/ml reduced rates of colorectal cancer by half, while raising levels to 46ng/ml cut the risk by two-thirds.
Optimizing your sun exposure and levels of vitamin D may, indeed, be one of the most important physical steps you can take in support of your long-term health, but it is important to understand that the ideal and STRONGLY preferred method of increasing your vitamin D level is through appropriate sun exposure. I really do not advise oral supplements, not even cod liver oil now, UNLESS you have your blood levels checked regularly.
Science Daily February 8, 2007