Vitamin deficiency disorders. Artwork of various disorders caused by vitamin deficiency. They are (clockwise from top left): the loose teeth and bleeding gums of scurvy (lack of vitamin C); an X-ray of the bowed legs reveals rickets (lack of vitamin D); deficiencies in vitamins like folic acid may occur during pregnancy; the skin inflammation and blistering of pellagra (lack of niacin); the large deformed red blood cells (pink) in the blood smear are due to megaloblastic anaemia (lack of folic acid or vitamin B12); cracked lips, swollen tongue and the spread of enlarged blood vessels over the eye (lack of riboflavin, or vitamin B2).