The Canadian Cancer Society lists vitamin D as protective against certain cancers such as colorectal and breast cancers1. Individuals can get vitamin D through exposure to sunlight, in the diet or through supplements. In 2008, The International Agency for Research on Cancer (IARC) published a report on the links between Vitamin D and certain cancers2. The report found a relationship between low vitamin D and colorectal cancer, and some evidence of the same relationship with breast cancer.
1. Canadian Cancer Society (2015) Vitamin D. Retrieved August 2015 from https://www.cancer.ca/en/prevention-and-screening/live-well/vitamin-d/?region=on
2. IARC (2008) Vitamin D and Cancer. Retrieved August 2015 from http://www.iarc.fr/en/publications/pdfs-online/wrk/wrk5/Report_VitD.pdf