Vitamin D levels, prostate cancer not linked
http://www.physorg.com/news/2011-02-vitamin-d-prostate-cancer-linked.htmlBut I do remember hearing that there was one vitamin that actually increases the risk and virulence of prostate cancer.
I'll go looking.
Dairy, calcium, and vitamin D intakes and prostate cancer risk in the National Health and Nutrition Examination Epidemiologic Follow-up Study cohort.
Abstract
BACKGROUND: Dairy intake may increase prostate cancer risk, but whether this is due to calcium's suppression of circulating vitamin D remains unclear. Findings on calcium and vitamin D intake and prostate cancer are inconsistent.
OBJECTIVE: We examined the association of dairy, calcium, and vitamin D intake with prostate cancer.
DESIGN: In a prospective study of 3612 men followed from 1982-1984 to 1992 for the first National Health and Nutrition Examination Epidemiologic Follow-up Study, 131 prostate cancer cases were identified. Dietary intake was estimated from questionnaires completed in 1982-1984. Relative risk (RR) and 95% CIs were estimated by using Cox proportional hazards models adjusted for age, race, and other covariates.
RESULTS: Compared with men in the lowest tertile for dairy food intake, men in the highest tertile had a relative risk (RR) of 2.2 (95% CI: 1.2, 3.9; trend P = 0.05). Low-fat milk was associated with increased risk (RR = 1.5; 95% CI: 1.1, 2.2; third compared with first tertile; trend P = 0.02), but whole milk was not (RR = 0.8; 95% CI: 0.5, 1.3; third compared with first tertile; trend P = 0.35). Dietary calcium was also strongly associated with increased risk (RR = 2.2; 95% CI: 1.4, 3.5; third compared with first tertile; trend P = 0.001). After adjustment for calcium intake, neither vitamin D nor phosphorus was clearly associated with risk.
CONCLUSIONS: Dairy consumption may increase prostate cancer risk through a calcium-related pathway. Calcium and low-fat milk have been promoted to reduce risk of osteoporosis and colon cancer. Therefore, the mechanisms by which dairy and calcium might increase prostate cancer risk should be clarified and confirmed.
More:
http://www.ncbi.nlm.nih.gov/pubmed/15883441 Prostate Cancer and Vitamin E
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The SELECT Trial
The SELECT (the Selenium and Vitamin E Cancer Prevention Trial) trial was the first large, well-organized, comprehensively controlled study that sought to evaluate the benefits of both selenium and vitamin E for prostate cancer prevention. The study was monitored and organized by several well-respected researchers and research groups.
The SELECT trial enrolled more than 35,000 men who were randomly assigned to one of four groups over the course of several years. One group took one selenium and one vitamin E tablet daily. One group took one selenium and one placebo tablet daily. One group took one vitamin E and one placebo tablet daily. One group took two placebo tablets daily.
The SELECT trial overall showed no benefit in terms of prostate cancer risk reduction from taking selenium or vitamin E supplements. In addition, the trial showed a slight increase in the rate of diabetes among the men who were taking selenium supplements and a slight increase in the rate of prostate cancer in the men taking vitamin E supplements.
Neither of these slight increases in medical conditions were found to be statistically significant (meaning these small increases could be due to chance), however, they were still troubling enough when coupled with the lack of benefit of the supplements for the trial to be stopped early and the participants to be told to cease taking their supplements.
Today
In large part due to the results of the SELECT trial, men today are generally no longer encouraged to take selenium and vitamin E supplements as a means to lower their prostate cancer risk.
Do vitamins increase the risk of cancer?
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That explains why vitamin supplements fail to prevent cancer. How would supplements act to cause cancer?
... using the folate supplementation trial as an example, it is not unreasonable to assume that optimal levels of folate are associated with more fidelity in DNA replication and thus a lower risk of spontaneous mutations, but high folate may also support more rapid cell growth and promote carcinogenesis in previously initiated cells.
Another possibility is that large quantities of specific vitamins or minerals may be consumed by particular types of cancer. In that case, low levels of that vitamin or mineral in cancer patients reflect the fact that the cancer needs the micronutrient. The level has dropped not because high levels of the vitamin or mineral prevent cancer, but because the cancer has used up what is available. Far from preventing cancer, supplements might actually feed the cancer and promote rapid growth.
Whatever the reason, it is clear that supplements do not represent the next frontier in cancer prevention. As the authors acknowledge:
More:
http://open.salon.com/blog/amytuteurmd/2010/04/01/do_vitamins_increase_the_risk_of_cancer Multivitamin use raises risk of advanced prostate cancer?
By Ben Wasserman
May 16, 2007 - 6:49:19 AM
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Men taking multi-vitamin supplements often may increase their risk of death from prostate cancer, according to a new study published in the May 16 issue of the Journal of the National Cancer Institute.
But experts caution that the study could not establish a causal relation between the risk and use of multivitamins, meaning multivitamin use does not necessarily raise the death risk associated with prostate cancer.
The study, a statistical analysis, but not a trial, found that men who used multi-vitamins more than seven times a week were twice as likely to die of prostate cancer as men who never took vitamins.
Those men were also at an increased risk of developing advanced or fatal prostate cancer, compared with men who never used multivitamins, reported Karla A. Lawson, Ph.D., of the National Cancer Institute and colleagues.
More:
http://foodconsumer.org/7777/8888/C_ancer_31/051606492007_Multivitamin_use_raises_risk_of_advanced_prostate_cancer.shtmlBut apparently multivitamin use was not associated with increased risk of developing prostate cancer overall, the study found.