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High Dose B12 - Prostate Cancer Risk?

Discussion in 'Detox: Methylation; B12; Glutathione; Chelation' started by arx, Mar 7, 2014.

  1. arx

    arx Senior Member

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    There appears to be a link between megadoses of vitamin B12 and certain cancers. One study showed that excess vitamin B12 intake was associated with a three-fold increase in risk of developing prostate cancer.

    http://psa-rising.com/eatingwell/vb12_folate04.html


    Folate and B12 were expected to be protective against prostate cancer, because folate, vitamin B12 and homocysteine are essential for methyl group metabolism and thus also for DNA methylation. Abnormal methylation, primarily hypermethylation of certain genes including tumor suppressors, has been implicated in prostate cancer development.

    But in fact, increasing plasma levels of folate and vitamin B12 were statistically significantly associated with increased prostate cancer risk, with an odds ratio of 1.60 for folate and 2.63 for vitamin B12 for highest vs. lowest quartile.

    Increasing plasma homocysteine levels were associated with a reduced risk of borderline significance.

    After adjustment for body mass index and smoking, a statistically significant increased risk remained only for vitamin B12.

    The researchers say: "Our results suggest that factors contributing to folate status are not protective against prostate cancer. On the contrary, vitamin B12, associated with an up to 3-fold increase in risk, and possibly also folate, may even stimulate prostate cancer development. These findings are novel and should be explored further in future studies."
     
  2. Lynn_M

    Lynn_M Senior Member

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    Western Nebraska
    The two studies cited in the psa-rising article seem to be prospective epidemiological studies. Epidemiological studies are good for raising questions but cannot prove anything.

    In the breast cancer study, they conducted biennial food frequency questionnaires, a notoriously inaccurate method for establishing dietary intake. They also did a one-time blood collection six years prior to the determination of which of the nurses in the study had breast cancer. They also seemed to lump together both synthetic folic acid from supplements and food additives together with folate from food. High levels of synthetic folic acid have already been shown to depress natural-killer cells, whereas that has not been shown to occur with food folate forms. The lumping together of all forms of folate may have confounded the relationship between non-folic acid folate levels and breast cancer incidence.

    The breast cancer study showed plasma B12 levels were inversely associated with breast cancer risk in premenopausal women, but not among postmenopausal women. Plasma B12 levels are the total of active and inactive forms of B12, so hard to know how much active B12 was in the plasma levels as opposed to the inactive form.
    In the prostate cancer study, not enough detail is given in the abstract to comment on their methodology. The same drawbacks of the breast cancer study may also apply here. I would think if something helped reduce risk for breast cancer, it would also help reduce risk for prostate cancer, so I find these different results paradoxical. If hypermethylation of certain genes including tumor suppressors is implicated in prostate cancer development, wouldn't it also be a factor in breast cancer development?

    I wonder what factors account for high B12 levels in the subjects of each study. Those factors may help explain the results.

    All that being said, if a nutrient is supplied in excess of what the body needs, the body has to work to get rid of it, and that excess could be considered as a toxin.
     
    whodathunkit likes this.
  3. Sea

    Sea Senior Member

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    I wonder also if they differentiated between methylfolate and folic acid and between methylcobalamin and cyanocobalamin.
     

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