A very small study found that some women with advanced-stage breast cancer had lower vitamin D levels than women with early-stage breast cancer. But this study is very small and it's difficult to know if the results apply to all women.
A much larger study Breastcancer.org reviewed in June 2006 didn't show a connection between reduced breast cancer risk and taking vitamin D and calcium supplements.
This study does NOT show that low vitamin D levels lead to advanced breast cancer. It also does not show that high vitamin D levels offer protection against advanced breast cancer. There appears to be a relationship between vitamin D levels and breast cancer progression. More research is needed to understand this relationship. Right now there is no evidence that vitamin D supplements reduce breast cancer risk.
No food or diet can prevent you from getting breast cancer. But some foods can make your body the healthiest it can be, boost your immune system, and help keep your risk for breast cancer as low as possible. Current research findings suggest that physical activity, a healthy diet, and a healthy weight can help reduce the risk of getting breast cancer for the first time.
For more information on changes you can make in your lifestyle and environment to reduce your risk of breast cancer, visit our Lower Your Risk section.