Recent evidence is reviewed indicating increased oxidative damage in Type 1 and Type 2
diabetes mellitus as well as deficits in antioxidant defence enzymes and vitamins.
Mechanisms are considered whereby hyperglycaemia can increase oxidative stress, and
change the redox potential of glutathione and whereby reactive oxygen species can cause
hyperglycaemia. It is argued that oxygen, antioxidant defences, and cellular redox status
should now be regarded as central players in diabetes and the metabolic syndrome.