Pantothenic acid, (vitamin $\mathrm{B}_5$ ) formerly known as chick anti-dermatitis factor or filtrate factor is widely distributed in nature. It is a water soluble vitamin needed for metabolism of carbohydrates, fats and proteins. It is found in egg, cereals, legumes meat, etc. It is a surprise to biochemists that despite the involvement of pantothenic acid (as coenzyme A) in a great number of metabolic reactions, its deficiency manifestations have not been reported in humans, presumably because of the wide occurrence of this vitamin in almost all foods and because small amount can be synthesized in the body. Folic acid deficiency is probably the most common vitamin deficiency.
The macrocytic anaemia (abnormally large $\mathrm{RBC}$ ) associated with megaloblastic changes in bone marrow is a characteristic feature of folate deficiency.