Vitamin C (ascorbic acid) crystals, LM

Polarised light micrograph of vitamin C (also known as ascorbic acid). Vitamin C is an antioxidant and protects cells from damage, improves absorption of iron and helps the immune system to work properly. Our bodies cannot make vitamin C, so we have to obtain it from food and drink. Vitamin C is used to make collagen, a protein found in many different tissues in the body. Too little vitamin C means that not enough collagen can be made, which causes skin, cartilage, bone and blood vessels to start to break down. This rare disease is called scurvy. Width of image is 1 mm.