The answer, from the Vitamin D Council is a resounding YES, not only because there are positive clinical trials showing that vitamin D prolongs life, but also because there are so many studies showing that it helps the pathological process. It will take decades to complete studies showing whether vitamin D increases overall cancer survival, but such studies are underway. In the meantime, most studies show that vitamin D helps with both cancer survival and prevention.
If you have breast cancer or you are trying to prevent breast cancer and want to take vitamin D, it is highly unlikely vitamin D supplementation will make your breast cancer worse or cause you any harm, assuming you take less than 20,000 IU per day. To help prevent breast cancer, women should achieve vitamin D blood levels of at least 60 ng/ml in the blood. This usually requires supplementation of 5,000 to 10,000 IU per day of vitamin D. After taking vitamin D for several months, obtain a blood vitamin D level to see if you are above 60 ng/ml.
If you currently have breast cancer, we recommend that you get your vitamin D blood level above 70 ng/ml. This will require anywhere from 5,000 to 15,000 IU/day. Make sure you check your vitamin D blood level after taking vitamin D for several months. Our low-cost in-home vitamin D blood test is an ideal way to monitor your vitamin D levels.