Women considered to be at high risk for melanoma could significantly reduce their chance of developing this potentially lethal skin cancer with daily doses of calcium and vitamin D. That's according to a Stanford study published today in the Journal of Clinical Oncology.
In the study, dermatologist Jean Tang, MD, PhD, and colleagues analyzed data from the Women’s Health Initiative (WHI), a large clinical trial that followed 36,000 women ages 50 to 79 for an average of seven years. During the WHI, half of the participants took daily doses of calcium and vitamin D and the remaining volunteers took a placebo pill as part of an experiment to evaluate effects of the dietary supplement on hip fractures and colorectal cancers. According to a release, Stanford researchers used the study data to zero in on women with a history of non-melanoma skin cancer and found:
Women who once had non-melanoma and took the calcium-vitamin D combination developed 57 percent fewer melanomas than women with similar histories who were not given the supplements.
[However], the study found that a daily dose of 1,000 mg calcium plus 400 IU of vitamin D doesn’t provide skin cancer protection for everybody. Women without a history of non-melanoma skin cancer who took the supplements did not see any reduction of risk compared with their placebo-group counterparts, according to the research.
The lack of protective effect in women without a history of non-melanoma skin cancer may be due to the amount of vitamin D given to the patients in the WHI trial... Furthermore, patients in the placebo group were allowed to take as much vitamin D as patients that were provided the calcium and vitamin D supplements, so the experimental difference between the two groups was small.
In light of these findings, Stanford researchers are pursuing additional studies to explore the relationship between vitamin D and cancer prevention. Research includes experiments comparing blood levels of vitamin D with melanoma outcome and examining the effect of larger doses of vitamin D on the behavior of skin cells in patients with high skin-cancer risk.