Dear Dr. Cannell:
I have low-grade prostate cancer and take vitamin D. I started taking 15,000 IU of vitamin D3 a day in 2007. I have reduced the amount of vitamin D3 from 15,000 IU to 10,000 ILI because my 25(OH)D in September 2010 showed 132. In October2011 my 25 (OH)D was 130 so I reduced it to 4500 IU a day.
In February 2012, it showed greater than 94 so my doctor told me to take about 3250 IU of vitamin D3 daily. Below are my PSA levels.
PSA Levels 2007-2012
Thank you for offering me the opportunity to help others, thanks for protecting my confidentiality and thanks for all you do.
Dear Mr. Smith:
Congratulations, your PSA is now near normal. In Dr. Marshal’s recent study, 4,000 IU per day kept PSA levels stable during the year of the study but 60% of the men showed biopsy improvement.
Marshall DT, et al. Vitamin D3 Supplementation at 4000 International Units Per Day for One Year Results in a Decrease of Positive Cores at Repeat Biopsy in Subjects with Low-Risk Prostate Cancer under Active Surveillance. J Clin Endocrinol Metab. 2012 Jul;97(7):2315-24. Epub 2012 Apr 16.
Since you started at such a high dose of vitamin D, and changed doses, it is difficult to know if your high blood levels were responsible for lowering your PSA. Your lowest PSA was when your level should have been about 80 ng/ml.
Though anecdotal, I had a patient, an African American man, whose PSA was 20. 5,000 IU/day appeared to bring it down to four over the next year. He then stopped the vitamin D and his PSA shot up to 18 over the next 6 months.
It appears the right dose of vitamin D may lower PSA levels in some men and that dose is more than 4,000 IU/day. It may require high normal 25(OH)D levels, around 80 ng/ml. Higher than that is not necessarily any better.