Q. What are the vitamins which make up the B complex? Which problems does the lack of these vitamins cause?

Vitamins of the B complex are: vitamin B1 or thiamin, riboflavin, or vitamin B2, and niacin (B3), essential for the constitution of the hydrogen acceptors FAD, NAD and NADP of the energetic metabolism pyridoxine, or B6 and cyanocobalamin or vitamin B12.

Deficiency of vitamin B1 causes beriberi loss of fatigue and appetite. The lack of vitamin B2 causes mucosal injuries in the mouth, lips and tongue. Deficiency of niacin causes nervousness, loss of energy and pellagra, digestive disturbances. Lack of vitamin B6 causes skin irritation, lesions and convulsions. Vitamin B12 acts together with folic acid and its deficiency causes cell division disruptions leading to pernicious anemia a type of nutrient deficiency anemia and megaloblastic.

The absorption of vitamin B12 depends on another substance called as the intrinsic factor secreted by the gastric mucosa.