Oxidative stress, micronutrients, diabetes mellitus and its complications.

Oxidative stress is defined as excessive production of reactive oxygen species (ROS) in the presence of diminished antioxidant substances. It has been shown that oxidative stress has an adverse effect on glucose metabolism. Development of the disabling chronic complications of diabetes mellitus (DM) has also been attributed to oxidative stress. The body's defence against oxidative stress is accomplished by interconnecting systems of antioxidant micronutrients (vitamins and minerals) and enzymes. While the vitamins act as donors and acceptors of ROS, minerals regulate activity of the enzymes. This review article is focused on the preventive and therapeutic roles of these antioxidant micronutrients in DM. Although there is scarcity of data from controlled studies, anecdotal reports indicate that the use of certain antioxidant vitamin and mineral supplements may be beneficial as an adjunct therapy in the management of DM and its complications. In particular, it has been reported that high doses of single micronutrient antioxidant supplements, such as vitamin E, may be beneficial to patients suffering from this disease. However, micronutrient antioxidants interact with each other in a biochemical chain of defence against free radicals, and the use of high doses of a single antioxidant poses potential risks because it could perturb the antioxidant-prooxidant balance. It has, therefore, been recommended that high doses of micronutrient antioxidant vitamins should be administered in combination rather than as single supplements. There are a growing number of preparations containing mixtures of antioxidant vitamins and/or trace elements. A particularly impressive supplement is a new formula called Akesis, which is a mixture of antioxidant vitamins and antidiabetic trace elements, adequately balanced with other vitamins and minerals that enhance metabolic processes.