Vitamin B12 Deficiency - A Real Shot In The Arm By Bantubantu at 24 Jul 2012 Post a Comment So, just what is Vitamin B12 exactly, and why do people need to have it? It is a vital nutrient that's found in food. It works to keep nerve ce… diarrheadoctorhealthhealthy lifenutrientsore tonguetiredvitaminvitamin b12weak