--you're aware that the B12 level you posted, though technically "in range", is much too low, right? (That could be the source of a whole range of symptoms.)

I don't know why labs still use that type of range for B12. Almost no other nation does--most labs in Europe and Japan mark the lower end of the range at somewhere around 450-550 ng/Dl, and the most savvy ones have no upper limit. Mrs. D's B12 thread is certainly full of papers and studies that indicate a number of people have B12 deficiency symptoms even when their levels are in the 400's or sometimes even higher. We should likely all aim for for B12 levels in the upper three digits to four digits.