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Dr of Golf
07-03-2003, 02:59 PM
Just thought I would share this Medical Information with all of you.

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From Medscape Physician's Medical News

Excessive Zinc Supplementation May Increase Prostate Cancer Risk

By: Laurie Barclay, MD


July 1, 2003 — Zinc supplementation may increase prostate cancer risk, according to the results of a study published in the July 2 issue of the Journal of the National Cancer Institute. Reviewing data from the Health Professionals Follow-up Study, the investigators suggest that zinc supplementation of 100 mg/day or more or use of supplements for more than 10 years can more than double the risk of prostate cancer.

"The high concentration of zinc in the prostate suggests that zinc may play a role in prostate health," write Michael F. Leitzmann, MD, from the National Institutes of Health in Bethesda, Maryland, and colleagues. "Whether dietary zinc intake affects intraprostatic zinc levels is unknown. However, ingestion of 150 mg/day or more of zinc has undesirable metabolic effects, such as immune dysfunction and impaired antioxidant defense that are potentially related to prostate cancer."

During follow-up from 1986 through 2000 of 46,074 U.S. men enrolled in the Health Professionals Follow-up Study, 2,901 developed prostate cancer, including 434 cases of advanced cancer.

Although supplemental zinc up to 100 mg/day was not associated with prostate cancer risk, men who consumed more than 100 mg/day of supplemental zinc had more than double the risk of advanced prostate cancer compared with nonusers (relative risk, 2.29; 95% confidence interval [CI], 1.06 - 4.95; P = .003 for trend). In men who used zinc supplements for at least 10 years, relative risk was 2.37 (95% CI, 1.42 - 3.95; P <.001 for trend).

"Excessively high zinc intake was associated with an increased risk of advanced prostate cancer," the authors write. "Although we cannot rule out residual confounding by supplemental calcium intake or some unmeasured correlate of zinc supplement use, our findings, that chronic zinc oversupply may play a role in prostate carcinogenesis, warrant further investigation."

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Journal of the National Cancer Institute. 2003; 95:1004-1007
Reviewed by Gary D. Vogin, MD
Laurie Barclay, MD is a Writer for Medscape Physician's Medical News

Tryska
07-03-2003, 03:09 PM
you shouldn't be taking more than 100 mgs of zinc in any case.

ElPietro
07-03-2003, 03:18 PM
So do any of these cancer research centres actually try and find a cure for cancer? Or are they content with millions of studies claiming what may or may not cause it, then they retract their studies a year later saying they were wrong, or it now "may not" cause cancer.

Sorry I'm not ranting on the poster of the article, just that it seems like cancer research is a multi-trillion dollar group of research companies and labs, and I bet if life on earth depended on a cure before the end of the year, they would be able to pool all their resources and find a definitive way to treat this affliction. Yet I'm sure they are content to sit on their billions and do research and find many other applications and patents to further make billions off of, meanwhile the general population (read: guinea pigs and test subjects) suffer millions of deaths in the interim.

Ok, I'm done now.

restless
07-03-2003, 03:44 PM
100 mg is a very high dosage isn't it? I don't take any zinc supplements and usually struggle to meet my RDA of it. Anyway, info is always welcome.

Tryska
07-03-2003, 03:47 PM
yes 100 is the highest you shoudl go.


what concerns me is how they did this research, and why didn't anyone stop these guys from taking more than 100mg and advise them to stay clsoer to 50mg, based on immuno-suppressive action alone?

restless
07-03-2003, 03:49 PM
Originally posted by Tryska


what concerns me is how they did this research, and why didn't anyone stop these guys from taking more than 100mg and advise them to stay clsoer to 50mg, based on immuno-suppressive action alone?

Well, if the purpose of the study was accessing the effects of beyond the recommended dosage supplementation then that would kind of defeat the purpose wouldn't it?

Blood&Iron
07-03-2003, 03:51 PM
Most pills are 30mg. That's what I take (NOW's L-Opti-Zinc, which also includes copper)

I've seen pills up to 50mg, though I've always avoided them.

Multi's, from what I recall, usually have around 15mg or so.

It's seems implausible folks would *accidentally* be getting over 100mg of zinc in their diets, even with supplementation--unless they're being ******ed.

If you're megadosing on zinc, you'll probably run into other problems before prostate cancer anyway:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12368702&dopt=Abstract

Tryska
07-03-2003, 03:57 PM
Originally posted by restless


Well, if the purpose of the study was accessing the effects of beyond the recommended dosage supplementation then that would kind of defeat the purpose wouldn't it?

yeah, my point was a study that would megadose men on zinc to find out if it causes prostae cancer seems like very hazy ethics to me.

restless
07-03-2003, 04:23 PM
Originally posted by Tryska


yeah, my point was a study that would megadose men on zinc to find out if it causes prostae cancer seems like very hazy ethics to me.

lol, yeah it does, but the drug industry is full of stuff like that. The subjects involved get paid so it's not like they're being forced to do anything. And anyway, we all profit from this hazy ethics, after all drugs are usually tested in beyond the recommended doses in humans after all the animal testing.

Dr of Golf
07-09-2003, 09:53 PM
Originally posted by restless


lol, yeah it does, but the drug industry is full of stuff like that. The subjects involved get paid so it's not like they're being forced to do anything.

Yeah, and a lot of college students help pay their tuition and such by being subjects in those studies. ;)