None have ever been proven useful for preventing PC, but Vitamin E has proved harmful in the incidence of PC. But after RP with no indication of residual disease, I seriously doubt that any vitamins would make any difference either way. I eat a heart-healthy diet, get plenty of exercise, and save the money many people waste on vitamins. In the US, it's a $25 billion industry with no proven benefit. Remember that over twenty times as many people die from heart disease than die from prostate cancer every year.
Some people like to take pills because it gives an illusion of control, and as long as they don't take large amounts, it's probably not harmful.
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None have proven useful? Thats not true
This is one of many - http://www.ncbi.nlm.nih.gov/pubmed/16080543
"There are now extensive scientific data suggesting the potential role of dietary and non-dietary phytochemicals in the prevention and control of prostate cancer (PCA) growth and progression."
Thanks, Tommy, for letting me address this issue -- I think it's important that everyone be able to distinguish what constitutes "proof" from what doesn't, especially because these days we all have access to so much information, and it is up to us to sort through it all and determine what is reliable from what is not. For doctors and scientists, "proof" involves large well-controlled, randomized, double-blind, prospective studies, preferably independently confirmed. Everything else falls into the category of "suggestive," as in the study you quoted (reading the first line of their abstract). Suggestive studies are a good starting ground for more rigorous investigation but don't prove anything by themselves.
Why have scientists, and the FDA, the USPSTF, and others put up all those requirements? Let's go through the requirements:
Large: Well, it must be large enough so that the differences are statistically significant. We've all seen polls that state they are accurate to within say ±4% with 95% confidence. A large sample size is necessary to be able to read the results.
Randomized:Statistics are only meaningful on random samples. Selection bias can confound the projectability of a study.
Well-controlled: both the treatment group and the control group (which does not receive the treatment) must be matched on a set of relevant demographic characteristics, so that we are not trying to compare apples to oranges. The findings are only projectable to the kind of people it was tested on.
Double-blind, controlled: Neither the patient nor the doctor can know if he is getting the treatment or the placebo or other control. Doctors who know they are giving the actual treatment may influence the outcome subconsciously. On the patient side, the placebo effect is very real -- people have been really cured by placebos. The treatment has to do significantly better than the placebo to be considered effective.
Prospective studies: Both groups must be treated the same way from the start. There are a multitude of extraneous variables that may influence results looking backwards (retrospective).
Replication: If only one investigator "proves" a treatment and all others don't, it leads us to question whether some unknown bias influenced the result that time. External validation is always desirable.
Time: Especially for PC, it's also necessary that the study run long enough to detect an effect, which can take 20 years or more. The results are only valid for the length of time the observation was made.
Here's a partial list of types of studies that do not constitute proof: retrospective studies, epidemiological studies, cohort studies, non-randomized studies, uncontrolled prospective studies, pilot studies, in vitro lab studies on tissue samples, in vivo lab studies on mice. They are all important steps along the way.
Because it's so hard to get real proof, the US National Institute of Health (NIH), the US Preventive Services Task Force (USPSTF), as well as other medical organizations have established "levels of evidence" to grade how reliable our data is. Rather than just decide if a treatment is proven or not, they judge its degree of proof on a scale. Here's the US government's criteria (Sections 4.3 and on) if you want to learn more about it:
A good example of a "proven" Vitamin effect is the SELECT study on the effect of Vitamin E and Selenium. It proved that Selenium supplementation had no effect and that Vitamin E supplementation had a slight deleterious effect.
An example of a study that does not constitute proof is the pomegranate juice study. There was no control group and no one was blinded. Was the decrease in PSA doubling time due to the placebo effect? Did investigators unconsciously pick or treat the patients differently than they otherwise might have. For me, it was especially troubling because it would have been so easy to establish a group of matched controls to receive colored, flavored sugar water or some other fruit juice. It didn't surprise me that the FDA did not allow POM Wonderful to make any health claims based on it. The way they conducted the research made me suspicious myself.
It's extremely troublesome and expensive to conduct studies that will constitute proof. Yet reliable studies do crop up occasionally. There's an interesting one on red yeast rice now, for example. Every grad student wants to make his name by proving the next big overlooked thing. I remember my disappointment in watching lycopene go down -- I had a cabinet full of tomato sauce! I still hold high hopes for a few dietary interventions like soy isoflavones, sulforaphane, red yeast rice, and apigenin. I think that future molecular alterations may render EGCG and curcumin useful too. After seeing Vitamin E proven harmful, I would never recommend to anyone an unproven dietary supplement, but I do monitor them closely and with hope.
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“It's extremely troublesome and expensive to conduct studies that will constitute proof.”
That’s a big part of the problem. There is no money to be made on funding a study for something wall mart sells for $2.00. I like Vitamin D as an good example, there is significant “proof” now that it helps in many areas that we didn’t even know about 5 years ago and vitamin D is certainly nothing new.
Pub med said “extensive scientific data”, thats pretty good news for someone facing cancer. I think to simply dismiss this is a disservice.
“There's an interesting one on red yeast rice now, for example.”
Yes I took 90 points off my cholesterol in 8 weeks with red yeast rice. Its been used safely in China for thousands of years. My doctor let my try that after I could barely move after 2 days on Lipitor.
Last edited by mod85; 02-15-2013 at 08:52 PM.
Reason: corrected the url
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. 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. "Extensive scientific data" doesn't mean there is any proof.
In a case-control matched study of over 1500 men for up to 8 years, researchers at 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. 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:
Another NCI/NIH-sponsored matched case-control study looked at 2,000 Finnish men over 20 years. Their 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/pmc/articles/PMC3188814/
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:
I have many such high quality studies on Vitamin D in my file, and 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?
You'll be happy to hear, though, that 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:
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 always suggest to my friends that they get their nutrients from well-balanced, heart-healthy foods and no more than 15 minutes of sunshine a day. Supplements can be as dangerous as any other drug and in my opinion, should not be used until the benefits are definitively proven.
A lot more work needs to be done on statins too. The scientific data so far has been equivocal albeit intriguing. Several studies suggest no benefit, some suggest they may act synergistically with other medications, and some suggest, but do not prove, a benefit. At least so far I haven't seen any that suggest statins are harmful for PC, as studies have for Vitamins D & E have shown. I eagerly await the results of the Red Rice Yeast study.
Last edited by Tall Allen; 02-16-2013 at 11:10 AM.
Reason: clarified that I was speaking to PC only
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