Vitamin D?

http://www.vitamindsociety.org/

http://www.vitamindcouncil.org/

Post Edited (Sagittarian) : 2/19/2013 12:17:10 PM (GMT-7)

Good valid point, not sure where ALL the funding comes from.

 

Studies about sun exposure and vitamin D has no financial gain.

 

Or should I say "I don't think so"

 

Wise observation, unfortunately there are always eyes on making a buck.

I don't know that they have any clinical studies on the matter.
There is a theory that prostate cancer is more severe in those with low vitamin d , including black men who can't generate much vitamin d due to dark skin.

This is an article that is interesting:
www.sciencedaily.com/releases/2012/03/120331151134.htme

Primary care doctor put me on D3, 1000 IU, daily for one year.

After a year the VIT D is within normal limits, year was one month ago.

I currently take 1000 IU daily.

I have heard a theory that Vitamin D is implicated in PC but not necessarily directly. In other words, there are data that show that low Vitamin D is correlated with higher rates and severity of prostate cancer but there are also data that cast doubt on whether Vitamin D supplementation is actually preventative, or therapeutic. Correlation does not prove causality. The implication is that perhaps the low vitamin D is the end result of some complex metabolic pathway, and that some *other* part of that same pathway is implicated in PC initiation and/or progression. That could explain both seemingly contradictory observations.

http://www.news-medical.net/news/20111117/Vitamin-D-and-its-good-and-bad-effects-on-the-heart.aspx

My PCP is monitoring Vitamin D to keep it within normal limits.

Don't just pop them like tac tacs, if your deficient you need it,

if not you don't.

 

You might try googling "therapeutic doses of (specific) vitamin(s)." I tend to gravitate toward the "journal articles." Don't know how close they might be to traditional medical journal articles, but I don't think they are on the other end of the spectrum near the snake oil claims either. For example:

ajcn.nutrition.org/site/misc/supplist.xhtml#2012

Vitamin D is a great example of a substance that has had a lot of studies, but no proven benefit to PC. There seems to be a lot of misinformation out there about Vitamin D on random internet sites. I pulled the following out of my recent files on the subject. I should also rush to add that there may be great reasons for supplementing Vitamin D – guys on Hormone Therapy, for example, although even that has been questioned.

It seems that much of the evidence supporting Vitamin D supplementation was extrapolated from lab studies on the cellular level and studies on rats. Sadly, the promise of those studies has never been duplicated in humans.

In a case-control matched study of over 1500 men for up to 8 years, researchers the National Cancer Institute (NCI/NIH) looked at the serum Vitamin D levels of men who were later diagnosed with PC vs those who remained PC-free. They concluded:

The findings of this large prospective study do not support the hypothesis that vitamin D is associated with decreased risk of prostate cancer; indeed, higher circulating 25(OH)D concentrations may be associated with increased risk of aggressive disease.

Here’s a link to their study. http://jnci.oxfordjournals.org/content/100/11/796.long
http://www.ncbi.nlm.nih.gov/pubmed/18505967
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3188814/

Another NCI/NIH matched case-control study looked at 2,000 Finnish men over 20 years. They conclude:

Our findings indicate that men with higher vitamin D blood levels may be at increased risk of developing prostate cancer. Impact: Greater caution is warranted with respect to recommendations for high-dose vitamin D supplementation and higher population target blood levels.

Here’s a link to an abstract of their study: http://www.ncbi.nlm.nih.gov/pubmed/21784952

Lest we think that Finnish men are somehow different, there was a large multi-ethnic study performed in California and Hawaii that included 329 men with PC and 656 matched controls. They found no overall association between levels of plasma Vitamin D and risk of PC, but those with the highest levels of serum Vitamin D were 50% more likely to have PC.

Here’s a link to the study: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2834847/


In the almost 10,000 person Prostate Cancer Prevential Trial that ran in the US and Canada from 1994-2003, there was no association found between dietary or supplemental intake of Vitamin D and risk of prostate cancer.

Here’s a link to an abstract of the conclusion. http://www.ncbi.nlm.nih.gov/pubmed/20693267

A similar study to the one above, called the European Prospective Investigation into Cancer and Nutrition (EPIC) was run in Europe in 23 centers ten European countries and included 153,457 men. It too found no association between Vitamin D intake and risk of PC.

Here’s a link to an abstract of the conclusion. http://www.ncbi.nlm.nih.gov/pubmed/20843485


In fact, I could only find two research studies that showed that higher plasma Vitamin D was associated with better PC prognosis. One was based on the Physicians Health Study which I, and many other researchers, have always considered a problematic non-random sample. In this study, those with lower serum Vitamin D had more advanced PC and higher Gleason score, and it would be valid to hypothesize that the lower serum Vitamin D may be a result of propensity to cancer rather than a cause.

Here’s a link to the study. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3071841/?tool=pubmed

The other was based on 106 patients at a single center in Canada:
http://www.ncbi.nlm.nih.gov/pubmed/21310302


All of the following are metanalyses – attempts to synthesize and draw conclusions from the many research studies on the relationship between intake or plasma levels of Vitamin D and risk of prostate cancer. None of them were able to demonstrate any association.

http://www.ncbi.nlm.nih.gov/pubmed/20629479
http://www.ncbi.nlm.nih.gov/pubmed/20473927
http://www.ncbi.nlm.nih.gov/pubmed/19939760
http://www.ncbi.nlm.nih.gov/pubmed/21203822
http://www.ncbi.nlm.nih.gov/pubmed/21835895

I'm sorry to say that none of them show any benefit to supplementing any kind of Vitamin D to supraphysiological levels and many suggest that it may be detrimental to PC risk. The reason I'm sorry is well, who wouldn't want a magic pill that can lower the risk or reduce the virulence of PC?
It is impossible to conclude that large supplemental doses of Vitamin D can help prevent or slow down PC, while there is some evidence that it may actually be harmful in that regard.

It is possible that men with PC have defective Vitamin D receptors (VDRs), but if that is the case, supplementing Vitamin D cannot be of any use.

It is still heavily researched. A quick search of clinicaltrials.gov showed me that there are 36 studies on the subject of Vitamin D and prostate cancer:
http://clinicaltrials.gov/ct2/results?term=Vitamin+D+and+prostate+canc er&Search=Search
Perhaps a trial will someday demonstrate that there is a subset of patients for whom Vitamin D supplementation may not be harmful and may even be helpful. So far, it looks like there may be more harm than benefit to excessive intake of Vitamin D.

I do not think it prudent or wise to supplement Vitamin D beyond the levels attained with 15 minutes of sun exposure and nutritional sources. BTW, there is a much stronger case to be made that excessive calcium intake should be avoided by those with known PC. Calcium is often paired with added Vitamin D in dairy products.

I’m sure there’s a lot more to the story, which research over the coming years will elucidate.