Vegans run low on B12, and their cells show it
Pooling 17 studies, vegan adults had significantly less B12 in the blood than omnivores and significantly more homocysteine, which builds up when cells cannot get B12.
What the study found
Vegans run lower on B12 and higher on the marker of shortage
Pooling 17 studies, vegan adults came out with significantly less B12 in the blood than omnivores and significantly more homocysteine, which builds up when cells cannot get B12. The gap is not only a low reading; it shows in what the body does with what it has.
The caveat · Rests on a marker folate also moves
The two most specific markers, methylmalonic acid and holotranscobalamin, pointed the same way but missed significance at p=0.06 and p=0.09, so the case rests on homocysteine, which folate and kidney function also move. The comparisons are observational, so other diet-linked differences remain live.