Video: Vitamin D and Prostate Cancer | Helpline Questions

Helpline Questions | Transcription

Hi, I'm Dr. Scholz.

The subject of vitamin D comes up frequently when talking about prostate cancer. Why is that? Well, probably because men with prostate cancer are often treated with hormonal therapy which causes accelerated calcium loss from the bones and that needs to be counteracted. Adequate vitamin D levels help improve the absorption of calcium from the intestine into the bloodstream. So everyone who is getting hormonal therapy, typically, is advised to take some calcium at bedtime and some vitamin D. 

The subject of vitamin D and metabolism and treatment is fast and very controversial. Some people claim it improves your immune system, it does all kinds of other magical things. I've seen this pattern over and over with all kinds of supplements where discoveries are made that they're necessary and then the public tends to go overboard and believe that massive amounts are going to be useful. The problem with that thinking is that massive amounts of anything are almost never useful, and so the appropriate approach, at least with vitamin D is to test the levels in the blood, and I don't know why that's not talked about more frequently. People talk about you should take a thousand or 2,000 or 5,000, or 400, but it really is predicated on whether or not your levels are low. And it turns out that the general population that I see (men in their 60s, 70s, and 80s) about 25% of men run low vitamin D levels—that is, below 30—and low vitamin D is going to mess up calcium metabolism and can have other deleterious effects. So, testing once a year should be an appropriate part of everyone's annual physical exam. 

If vitamin D levels are low I would recommend starting 1,000 to 2,000 units a day and then retesting after about three or four months. It takes a while for new levels to equilibrate once the vitamin D has been started. You can't check it a week or two later. And then once normal levels are achieved periodic rechecks are necessary to ensure that it is maintained and also to make sure that the levels don't go too high. 

So, in summary, vitamin D is a very appropriate thing for men with prostate cancer, especially those that are on hormonal therapy. But it starts by checking blood levels, not by picking some arbitrary amount of 1,000, 2,000, 5,000 units a day because your levels may already be adequate and getting too much vitamin D is a potentially negative thing that could lead to problems instead of becoming a solution.