How do you know you are deficient in Vitamin B12? Written by Dr Harold Gunatillake –Health writer How can one tell or suspect that you lack vitamin B12? You may develop pins and needle sensations in your hands, and lower extremities unsteady walking disability, headaches, pale skin or being breathless and fatigued for no reason. Then, think that you may be suffering from Vitamin B12 deficiency. Fatigue may be common in other illnesses or just due to lack of exercise, but fatigue or tiredness with vitamin B12 deficiency is accompanied with other symptoms mentioned. With further time with no diagnosis made, you may get confused; have cognitive impairment, paranoia, delusions, mania, psychosis, memory loss, incontinence when passing urine and loss of taste and smell. Vitamin B12 deficiency can cause severe irreversible damage to the brain and nervous system, if the blood levels go down to its lowest limits. It is ...