Could vitamin D help increase survival from breast cancer?

The authors aimed to determine whether or not vitamin D could protect women against breast cancer or if it could improve a patients chances of survival.

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer-related death among women. Lifestyle factors such as diet and exercise may impact the risk of breast cancer.

Previous studies have suggested that vitamin D may act as an anti-cancer agent against several cancers, including breast cancer. Vitamin D is availble in food or supplements, but can also be produced by the body in response to sunlight. This form of vitamin D is reported to potentially suppress (inhibit) tumor growth. 

This study aimed to determine the value of vitamin D in improving the prognosis (outlook) of women with breast cancer.

Over 6092 women with breast cancer were evaluated from a total of 30 studies.

Overall, results showed that vitamin D was weakly associated with lowering the risk of breast cancer. Vitamin D was strongly associated with improved chances of survival among the women with breast cancer. The risk of death due to breast cancer decreased by 42% for high versus low levels of 25(OH)D (vitamin D is converted to this once in the body). The risk of death due to any cause decreased by 39%.

Exercise may also have effect. A higher body mass index (BMI, a measure of body fat that takes height and weight into account) is associated with lower levels of 25(OH)D. Physically active patients are also more likely to be out in the sunshine, which leads to increased vitamin D production.

The study concluded that high levels of vitamin D are associated with improving prognosis among women with breast cancer, but it does not lower the overall risk of developing breast cancer.

If you have just received a breast cancer diagnosis or if you are already receiving treatment, you may be interested in discussing with your doctor the impact vitamin D supplements may have on your prognosis.