You wrote to us about a Journal article from 2009, which implies that in two academic studies from Norway, there was a higher incidence of cancer in the groups of patients receiving folic acid and also folic acid and B12.
We know from our own patients that B12 actually protects against cancer and may even cure it, so this finding surprised us. However it also surprised the authors, who are quick to point out that the preventative effect of B12 in protecting against cancer was observed in studies in USA.
Dr Chandy and myself are working on a chapter in the book on cancer, which explains how B12 is essential for consistent expressions of genes and correct transcriptions (reducing mutations). Of course it forms the basis of our interpretation of this paper, and you could accuse us of bias.
- Folic acid has been highlighted as potentially dangerous as a supplement, because the synthetic form used for supplementation (ie not natural folate) may not be the biologically active form and may deplete various coenzymes because they are a different form. If you know a lot about biological molecules, you will know that not only do they come in right-handed and left-handed forms, but there are often other differences (for example, phytocobalamins are as toxic to B12 metabolism as Carbon Monoxide is to oxygen metabolism (respiration) – they substitute and block the transport or metabolism.
- In the paper you cite, the level of folic acid supplementation is only just below the maximum tolerated level (the paper explains this). The maximum level is for folate ie natural B9, not taking into account that whilst many folic acids are acceptable to the body, there’s no mention of the form used in these trials and this paper.
- If you check the tables, the data clearly shows that B6 supplementation gives people the wanderlust – during the trial 3x as many people decided to emigrate from Norway and lost to the trial. But the authors didn’t highlight that because unfortunately it doesn’t make good clickbait. The data also show that B6 by itself is extremely effective against cancer. But the statistical analysis combines groups and says that this isn’t a real effect
- We know from our work that B12 can (often does) restore the body’s ability to absorb folate. This could cause problems if the liver coenzymes are tied up with inappropriate forms of folic acid. We found that (by checking blood levels) within a few months of supplementing with both B12 and folate, we stopped the folate. From then on, we stopped supplementing folate even though blood levels of folate would quickly restore to healthy levels but using natural folate instead of synthetic folic acid
- Our own work shows that B12 reduces incidents of cancer, although this was most pronounced with GI and rectal cancers. The authors of the paper you cite point out that their Norway study is very different from all of the studies of work done in USA. They haven’t even said “more research needs doing” which researchers always say, which makes me think they are a little embarrassed about how they interpreted the data. Certainly looking at their own data presented in the published tables in the document, I don’t come to the same conclusions