Vitamin B12, Cobalamin, Deficiency, Symptoms, Anemia, Nerve Damage, Malabsorption
B12 is essential for the production of red blood cells and aids in the maintenance of a healthy nervous system. B12 deficiency damages the brain, spinal cord, peripheral nerves, and nerves of the eye.
Interestingly enough the stubbornness and lack of agreeableness in general, and outbursts of rage, are all attributed to veganism as well. Not a pretty sight.