Top 10 Facts About Vitamin D and Cancer:
1. Many studies have found solar ultraviolet-B (UVB) vitamin D associated with reduced risk of breast, colon, and rectal cancer.
2. A randomized controlled trial with 1100 IU/day vitamin D3 plus 1450 mg/day calcium found a 77% reduction in all-cancer incidence.
3. Geographical studies have found reduced risk in mortality rates for 15-20 types of cancer in regions of higher solar UVB doses.
4. Observational studies found risk of breast, colon, and rectal cancer falls as vitamin D blood levels rise to over 40 ng/mL (100 nmol/L).
5. Mechanisms have been proposed to explain how vitamin D acts to reduce the risk of cancer from starting, growing, and spreading.
6. Those who develop non-melanoma skin cancer may have produced enough vitamin D to reduce their risk of internal cancers.
7. Those with higher vitamin D blood levels at time of cancer diagnosis had nearly twice the survival rate of those with the lowest levels.
8. African Americans have an increased risk of cancer in part due to lower vitamin D blood levels because of darker skin.
9. Higher UVB exposure early in life has been associated with reduced risk of breast and prostate cancer.
10. Those diagnosed with breast, colon, and prostate cancer in summer in Norway had higher survival rates than those diagnosed in winter.
Source: http://www.vitamindcouncil.org/health-conditions/cancer/