[Influence of dietary intake on plasma biomarkers of oxidative stress in humans].

Oxidative stress is related to an imbalance between the production of reactive species and the antioxidant defenses. In essence, oxidative stress has been defined as a disturbance in the pro-oxidant/antioxidant balance, leading to potential damage. It has been suggested that oxidative stress is involved in the etiology of several chronic diseases including cardiovascular disease, diabetes, cancer and neurodegenerative processes. The antioxidant defenses include nonenzymatic (especially dietary antioxidants) and antioxidant enzymes. Vitamins, minerals and phytochemicals (polyphenols and carotenoids) are among the major dietary antioxidants. The assessment of oxidative stress status though specific biomarkers has acquired great importance. The major biomarkers include the products of the attack of free radicals and reactive species to various substrates: lipids, proteins and nucleic acids. Measurement of antioxidant capacity may also involve the assessment of specific oxidative stress biomarkers. Most of the studies that have examined the association between diet and oxidative stress consider the effects of antioxidant supplements (vitamins and minerals), drinks and foods with bioactive compounds or dietary patterns on oxidative stress biomarkers. Some of these studies have demonstrated beneficial results on oxidative stress markers. However, the role of diet on oxidative stress biomarkers remains unclear and represents a potentially fruitful area for further research in the health area.