Vitamin C. Polarised light micrograph of a section through ascorbic acid (vitamin C) crystals. Ascorbic acid is a naturally occurring organic compound and is one form of vitamin C, an essential vitamin that is found in fruit and green vegetables. It is needed for the growth and maintenance of bones, teeth, skin and blood vessels. It is also a powerful antioxidant. Deficiency in vitamin C leads to scurvy, which causes bleeding gums and anaemia. Magnification: x200, when printed 10 centimetres wide.