It was found previously that low vitamin D levels increase the risk of developing breast cancer. Recently it has also been found that low vitamin D levels are associated with markers of more aggressive disease and of metastases. (Aggressive Breast Tumors Linked to Vitamin D Deficiency: April 29, 2011, at http://www.urmc.rochester.edu)
Women with vitamin D levels below 32 ng/ml had a higher percentage of hormone negative cancers, known to be more aggressive. They also had a higher Onco Dx score, a genetic test of cancer cells that predicts the likelihood of metastasis.
In other words, higher vitamin D levels not only lessen the chance of getting breast cancer, but will likely also improve survival in those who have breast cancer.
Protective vitamin D levels lie between 55-80 ng/ml. Toxicity does not develop from vitamin D until levels reach over 150 ng/ml. We suggest that all individuals have their vitamin D levels measured.
It is difficult to attain optimal vitamin D levels without taking a supplement. Five thousand units of vitamin D daily will be sufficient for most people. However, it is best to measure the blood level to verify adequacy.
Allan Sosin MD
Vitamin D is available in liquid drops, capsules and gelcaps in our online store.