5. You have a yellow hue
If you normally have healthy coloring, but lately, it looks as if your complexion is yellowish in color, it could be because you are suffering from a vitamin B12 deficiency.
As already stated, B12 aids in the production of red blood cells, which not only means you produce less but also means that the cells you do produce are delicate and break easily.
This can lead to an increase in bilirubin production, which can make your skin have a yellowish appearance. The whites of your eyes may look as if they are yellowish, too.