B12 and increased cancer risk?

On November 17, 2009, in General Nutrition, Water Solubles, by Andrea

It’s Tuesday.  Tuesday is a day that I work one of my real jobs.  You know, one that pays actual money that helps feed the younglings, keeps the bank from taking away the home, etc.  So I almost missed (yeah, right!) the flurry that JAMA kinda started within a few of the WLS circles about B12 and folate increasing cancer risk.  In fact, there were a few articles.. one here, and another here..

Actually, no, I couldn’t have missed it.  I think I got 2 or 3 emails.  Plus Beth posted about it on her FB and Twitter.  I’m sure it will be everywhere tomorrow.

So yeah, I read the article.  Sorry, it’s locked down and I am too broke to afford getting in trouble by breaking copyrights.  I’m adventurous, but not that adventurous.  You’re welcome to read the free abstract here.  The conclusion from the abstract is thus:

Results During study treatment, median serum folate concentration increased more than 6-fold among participants given folic acid. After a median 39 months of treatment and an additional 38 months of posttrial observational follow-up, 341 participants (10.0%) who received folic acid plus vitamin B12 vs 288 participants (8.4%) who did not receive such treatment were diagnosed with cancer (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.03-1.41; P = .02). A total of 136 (4.0%) who received folic acid plus vitamin B12 vs 100 (2.9%) who did not receive such treatment died from cancer (HR, 1.38; 95% CI, 1.07-1.79; P = .01). A total of 548 patients (16.1%) who received folic acid plus vitamin B12 vs 473 (13.8%) who did not receive such treatment died from any cause (HR, 1.18; 95% CI, 1.04-1.33; P = .01). Results were mainly driven by increased lung cancer incidence in participants who received folic acid plus vitamin B12. Vitamin B6 treatment was not associated with any significant effects.

Now, I have to tell you, I read the article.  And while I’m not an expert — and will never claim to ever be an expert cause God only knows how many emails I’d get then — it seems that the correlation is based on blood serum values for folate and cobalamin (B12) rather than the actual taking of the supplements.  I mean, actually I think a trained monkey could figure this out, although you’d have to read the entire article to get that because the abstracts aren’t giving it to you — gotta love scare journalism.  So for those of you injecting yourself weekly with B12 because your numbers suck — I’d not worry too much, although the numbers that correlated in the study are below what many of us postops look for as “ideal”.

In the folic acid groups, median serum folate increased from 3.9 to 27.5 ng/mL and serum cobalamin from 477 to 761 during the intervention.  In the vitamin B6 groups, median plasma pyridoxal 5′ phosphate (the active form of vitamin B6) increased from 8.2 to 75.4 ng/mL.

These can be scary numbers given that many docs see a “normal” B12 reference range as 200-600, folate as >5, and B6 from 5-30.  Some of these are not really off the mark too much.

Admittedly, there are several questions raised; many of the patients who developed lung cancer used to smoke – could this have caused a change in outcome?  Norway does not enrich their bread like the US does to avoid birth defects – could a massive dosage increase of these vitamins have made a difference?  I mean, these were massive differences compared to what we in the US are used to just by having a sandwich.

Because use of vitamin supplements was modest (23%) at trial entry and there is no folic acid fortification in foods in Norway, baseline serum folate levels were lower than in populations from areas where use of vitamin supplements is more widespread and fortification is voluntary or mandatory.  The intervention dose of 0.8 mg/d of folic acid was 4 to 6 times higher than the average dose delivered by the mandatory fortification in the United States and twice the recommended daily allowance.  Still the intervention dose was below the tolerable upper intake level of 1mg/d as set by the US Institute of Medicine. Our findings are therefore relevant across folic acid intake readily obtained from consumption of fortified foods and dietary supplements.

Yeah.  Vitamins and these.  I’m kinda screwed.

Come to mama..

Come to mama..

(If you didn’t know, these are chock full of B-vites — in fact, think of them as a slightly carbonated, caffeinated b-complex!)

I’m still not convinced that postops need to worry too much about this right now — especially given our predisposition to dropping B-vitamin levels anyway.  I think a known problem (especially that whole coma and death thing?  SOOO very inconvenient..) versus a possible one is something we should avoid at all costs — and hey, given these numbers, I should have been dead two years ago already.

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1 Response » to “B12 and increased cancer risk?”

  1. [...] But regardless — people, and these are people with little letters after their names, folks — not just me — people are saying that B12 in excess is not necessarily a great thing.  Especially with that whole JAMA deal that came out last week… [...]

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