Is there a future for antioxidants in atherogenesis?
Antioxidants, preferentially those of dietary origin, have for a long time been considered to help against diseases that are presumably aggravated by oxidative stress, such as cardiovascular diseases, cancer, and neurodegenerative disorders. The outcome of clinical trials undertaken to corroborate this hypothesis, however, remained largely inconclusive. Evidence is now emerging that some dietary "antioxidants" influence signaling pathways and the expression of genes relevant in atherosclerosis by mechanisms other than antioxidative ones. By concrete examples we show that (1) vitamin E has gene regulatory functions which might be more important than acting as an antioxidant in vivo, (2) selenium itself is not an antioxidant at all, and even not in general when incorporated into glutathione peroxidases, and (3) a moderate oxidative stress is beneficial rather than detrimental since it can induce defense mechanisms counteracting xenobiotic and oxidative stress. Thus, there is only a future for antioxidants in the prevention of any disease if their real mechanism of action is considered and suitable read-outs and biomarkers are established.
Brigelius-Flohé
Regina
R
Department of Biochemistry of Micronutrients, German Institute of Human Nutrition, Potsdam-Rehbruecke, Germany. flohe@mail.dife.de
Kluth
Dirk
D
Banning
Antje
A
D000975:Antioxidants / Q000008:administration & dosage / Q000627:therapeutic use; D050197:Atherosclerosis / Q000517:prevention & control*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004032:Diet; D041981:Gastrointestinal Tract / Q000201:enzymology; D005786:Gene Expression Regulation / Q000187:drug effects; D005979:Glutathione Peroxidase / Q000737:chemistry / Q000502:physiology; D006801:Humans; D018384:Oxidative Stress; D012643:Selenium / Q000008:administration & dosage / Q000737:chemistry; D015398:Signal Transduction; D014810:Vitamin E / Q000494:pharmacology
D000975:Antioxidants; D014810:Vitamin E; D003577:Cytochrome P-450 Enzyme System; D005979:Glutathione Peroxidase; D012643:Selenium