Cobalt is a component of vitamin B12, a nutritional factor necessary for the formation of red blood cells. Recent research in vitamin B12 has shown that its pink colour is attributed to the presence of cobalt in it. The presence of this mineral in foods helps the synthesis of haemoglobin and the absorption of food- iron. The best dietary sources of cobalt are meat, kidney and liver. All green leafy vegetables contain some amount of this mineral. No daily allowance has been set. Only a very small amount upto 8 mcg. is considered necessary. ? The human body contains 30 to 35 mg. of manganese, widely distributed throughout the tissues. It is found in the liver, pancreas, kidney, pituitary glands. This mineral helps nourish the nerves and brain and aids in the coordination of nerve impulses and muscular actions. It helps eliminate fatigue and reduces nervous irritability. Manganese is found in citrus fruits, the outer covering of nuts, grains, in the green leaves of edible plants, fish and raw egg yolk. No official daily allowance of manganese has been established, but 2.5 to 7 mg. is generally accepted to be the average adult requirement. A deficiency of this mineral can lead to dizziness, poor elasticity in the muscles, confused thinking and poor memory.