Fatigue and Weakness
Fatigue and weakness are one of the most commonly present symptoms of vitamin B12 deficiency. Weakness occurs as the body has lesser amounts of vitamin B12 to produce enough red blood cells that transport oxygen across the body. Therefore, you are not able to transport oxygen to body cells in an efficient manner thus making you fell weak. In case of elderly, an autoimmune condition like pernicious anemia is the main reason behind vitamin B12 deficiency. People having pernicious anemia are unable to produce adequate amounts of intrinsic factor to absorb vitamin B12 from the foods in the small intestine.