There has been a disturbing number of research studies suggesting that increased calcium consumption increases the risk of prostate cancer.
That has especially been a concern for those (including me) taking calcium along with a bisphosphonate drug (like Fosamax, Actonel, Boneva, Aredia, Zometa) and vitamin D3 as part of a program to counteract the decrease in bone denisty as a consequence of hormonal blockade therapy for prostate cancer.
It seemed we had to choose our risk, and I was hoping the docs were right who reckoned that you could decrease any risk if you took an appropriate amount of vitamin D.
Well, a newly published report, already in www.pubmed.gov, indicates strongly that there is no increased risk
from consuming calcium, at least as far as developing prostate cancer is concerned. The report is based on the kind of massive
long term research on prostate cancer that only the Scandanavian systems are well prepared to handle. The researchers enrolled 22,391 healthy Swedish men in the study and followed them for 30 years until December 2006. During those years, 1,539 of the men developed prostate cancer. But the chance for developing prostate cancer was virtually the same whether the men consumed a lot of calcium or a little.
Here's the citation for the study: Serum calcium and the risk of prostate cancer. Halthur C, Johansson AL, Almquist M, Malm J, Grönberg H, Manjer J, Dickman PW. Cancer Causes Control. 2009 Apr 18. [Epub ahead of print]
We are not completely out of the woods on this issue.
For example, one recent study found a significantly increased risk of death
from prostate cancer as levels of calcium in the blood increased.
However, in contrast, that same study found that the risk of getting prostate cancer
for men with high calcium levels was about the same as for men with low calcium levels, and that finding is consistent with the Swedish study.
(That's based not only on the risk values but on the value that shows the results were very likely the result of chancer rather than a real difference.) Here's the citation for this study: A prospective study of total and ionized serum calcium and fatal prostate cancer. Skinner HG, Schwartz GG. Cancer Epidemiol Biomarkers Prev. 2009 Feb;18(2):575-8. Epub 2009 Feb 3. (We need to give moral support to those unfortunate researchers, as they no doubt need it because they work at the University of Wisconsin, our Dairy State.
I feel more confident about the calcium supplements I take, but I'm sure going to keep taking that vitamin D!