Examination of blood of a person suspected of having anaemia, shows...

Anaemia is marked by an abnormally low haemoglobin concentration. The most common cause is deficiency of iron which is an essential element of the haemoglobin molecule. Thus, the iron compounds in the diet will help to alleviate the symptoms of anaemia. Thiamine (vitamin $\mathrm{B}_1$ ), deficiency causes beri-beri. Riboflavin (vitamin $\mathrm{B}_2$ ) deficiency causes cheilosis and skin diseases. Cobalamine (vitamin $\mathrm{B}_{12}$ ) deficiency causes pernicious anemia. Folic acid (vitamin $B_9$ ) causes anaemia.