2. Pale or yellow skin
As tissue oxygenation decreases due to a lack of fully-matured, healthy red blood cells in the body, the skin may take on a peculiar color that can be described as “pale”. Even light-skinned people become paler than usual, and the skin might have a sickly hue.
It is possible to develop yellow skin when the reserves of vitamin B12 are borderline and almost depleted. A yellowish shade can be noticeable not only on the skin, but also in the whites of the eyes.