Originally titled "Could B12 supplementation affect dna test results for B12 need?" - B12 just seems like a good example question to frame the more general question of "Can supplements affect DNA?"
I recently got a DNA test done from DNAFit and found out I do not have a raised need for B12 - however - I've been supplementing with about 10,000% B12 (as methylcobalamin) for quite some time now. Been taking 10,000% every day for 5 months and like 1,000+% B12 for another 5.5 months before the increased dosage. I actually am quite dependent on my supplements, and think it's quite possible that my DNA has adapted to them, if DNA does such things. (Just looking briefly, it appears there is some disagreement as to whether DNA can change due to supplementation: google.com/search?q=CAN+SUPPLEMENTS+CHANGE+DNA )
So there's the root of the question - can supplements affect DNA - more specifically - could B12 supplementation affect the result of my MTHFR genotype (which is CC, just FTR)