Breast cancer: vitamin D reduces mortality cases

In breast cancer patients, high concentrations of vitamin D are associated with low mortality rates. Women with the disease and high levels of a metabolite of the vitamin, 25(OH)D (25-hydroxycholecalciferol), have twice the survival rate of those with lower concentrations. Thus, vitamin D could become an adjuvant to conventional anticancer therapies.

This was discovered by researchers at the University of California, San Diego (USA). The meta-analysis study, published in the journal Anticancer Reresearch, was conducted on the results of five clinical trials.

Vitamin D and breast cancer

Vitamin D is found in many foods of animal and plant origin, and exists in two forms ergocalciferol or vitamin D2, and cholecalciferol or vitamin D3. Its main function is to maintain normal levels of calcium and phosphorus in the blood and to promote calcium absorption by helping to maintain healthy bones. Numerous findings have suggested that vitamin D may also have a protective role against hypertension, cancer, and various autoimmune diseases. In particular, recent studies have shown a link between low Vitamin D levels and an increased risk of premenopausal breast cancer.

More vitamin D, more chance of survival

Statistical analyses of the study were conducted on data obtained from 4443 patients, considering vitamin D concentration at the time of diagnosis and over the 9-year follow-up period. The researchers classified the women according to cholecalciferol concentration; those with the highest level had an average of 30 ng/mL, those with the lowest level 17 ng/mL. Previous studies have shown that the average Vitamin D concentration in breast cancer patients was just 17ng/mL The meta-analysis revealed that women in the group with higher Vitamin D levels showed half the risk of death compared with those in the group with the lower levels. 

The study results show that adequate serum vitamin D concentration is associated with lower mortality in breast cancer patients. However, it cannot be ruled out that these results may be due to reverse causality: it is possible that in more severe cases, and thus with earlier death, the serum concentration of 25(OH)D is lower. If so, vitamin D could be a signal molecule of cancer in severe form, rather than a factor that caused longer or shorter survival, Further studies will be needed to understand this relationship, but pending these there are no contraindications for recommending vitamin D supplements such that a serum concentration above 30 ng/ml is reached.   

Source: Sharif B. Mohr, Edward D. Gorham, June Kim, Heater Hofflich and Cedric F. Garland "Meta-analysis of Vitamin D Sufficiency for Improving Survival of Patients with Breast Cancer" Anticancer Research. March 2014 vol. 34 no. 3 1163-1166