Too much Vitamin D can be a problem for prostate cancer

I have written and lectured about vitamin D extensively. As a subscriber of the community, you know I am a huge proponent of vitamin D supplementation and avoiding vitamin D deficiencies like the plague. There is, however, some concern over too much vitamin D in men with prostate cancer.

Recently, in my practice, I have seen prostate cancer positive men with higher than normal blood levels of vitamin D (normal is 30 to 100ng/ml) presenting with a significant spike in their PSA. This has been a recent observation in my practice along with other online reports.

This may be a case where if a little is good, more is NOT better.

Recent scientific reviews have suggested that, although vitamin D for prostate cancer prevention is important as reflected by epidemiological and pre-human studies , human studies have not been consistent. (Barnett et al. 2011 & Swami et al. 2011)

What to do

The dosage of vitamin D you should take should not be predicted by the amount in a pill but but by the amount in your blood. A blood test, 25 Hydroxy – vitamin D is the best predictor on how much vitamin D you should consume.


An African-American male, 5’10 inches tall and 230 pounds much from body fat, will need more than a white male 6’0 180 pounds lean male. So while 10,ooo units is appropriate for the first guy, 5000 units is enough for the second guy.


What is optimal blood levels? Until further research is brought forth my new optimal blood level for patients is 40 – 60 ng/ml. For some people this may be a supplement pill of 5000units and for others it may be 10,000units.


In Optimal Health,

Dr. Geo

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