High B12 and breast cancer risk? - Pernicious Anaemi...

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High B12 and breast cancer risk?


What the heck?! After a very low b12 of 200 in 1995 with symptoms, I’ve been supplementing with methyl b12 sublingual for years and ignored my high serum b12 (is that the same as plasma levels?). I don’t understand everything here at this link but it seems to say high b12 puts people at risk....is it come super-methylated somethingorother? (I was Dx’d with stage one grade one lobular breast cancer July 3.

I’ve been trying to get a referral to a hematologist for years. Now that I have DNA issues in the form of cancer I’m pissed that my GP and GI would not pay freaking attention to me when I asked why my R Ca were too large and too few and MCH and MCV too high, even with b12 supplementation. I coupled it with 400 folate the last year or two and wasn’t super regular with either the past 6 months.


3 Replies
clivealiveForum Support

Hi Ashweb901 I read (or miss-read) it the other way round - having low levels of B12 and B9 may increase the risk of BC - but then I'm not a medically trained person.

"Vitamin B12 status was also positively associated with BC risk in women with plasma folate levels below the median value (ORQ4‐Q1 = 1.29; 95% CI 1.02–1.62; Ptrend = 0.03). Overall, folate and vitamin B12 status was not clearly associated with BC risk in this prospective cohort study".

Hopefully someone more qualified will be able to advise you.

I'm sorry to read about your cancer diagnosis and hope all goes well for you.

Best regards,

Thank you, clivealive! I will definitely have to get a doctor to interpret this document. In my additional research, I gleaned that to the extent that the B12 and folate can influence DNA repair and synthesis, if someone has one of the MTHFR polymorphisms (I do - I’m homozygous for a1298c) the methylation ability or lack thereof can influence risk for cancer and/or the growth of it once it is there.

All cryptic, but confirmed what we all know — this b12 and folate stuff MATTERS. A lot

more than your average GP or gastro or neuro will admit.

Still noodling over this.... What about these (isolated) statements?

"A marginally increased risk of BC associated with increasing concentrations of plasma vitamin B12 was found in women with plasma levels of folate below 13.56 nmol/l (ORQ4‐Q1 = 1.29; 95% CI 1.02–1.62; Ptrend = 0.03), while no significant association occurred in women with higher levels of plasma folate (Ptrend = 0.68). "


"As a cofactor required for the generation of methyl groups, a high vitamin B12 status could result in hypermethylation of CpG island promoters for tumor suppressor genes,44 which may lead to reduced expression of these cancer‐related genes and ultimately promote breast carcinogenesis.45 These DNA methylation changes may also impair the proper expression and/or function of cell‐cycle regulatory genes and thus confer a selective growth advantage to neoplastic cells.46 A randomized crossover trial suggested that moderate alcohol intake may diminish plasma vitamin B12 concentrations.47 In contrast, a case–control study found that plasma levels of vitamin B12 in heavy alcohol drinkers were significantly higher than those in light alcohol drinkers.48 Further studies are needed to clarify the modifying effect of alcohol on the association between vitamin B12 and BC risk."

That second one -- anyone here ever heard of high plasma B12 with high alcohol consumption? Is this because alcohol wrecks folate absorption from food?

I need to search this forum for mentions of hypermethylation, because that term has come across my radar before when researching MTHFR variants.

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