Effects of vitamin E and carotenoid status on oxidative stress in health and disease. Evidence obtained from human intervention studies.
Vitamin E and carotenoids are known to act as antioxidants both in vitro and in vivo. In this review we present a series of studies in healthy subjects and in patients who exhibit either acute or chronic oxidative stress. In the EU-Commission funded VITAGE project we investigated the status and effects of vitamin E and carotenoids on oxidative stress in 300 healthy volunteers. Depletion studies limiting dietary vitamin E or carotenoid intake to approximately 25% of the dietary reference intakes and subsequent repletion by supplementation with either large doses of vitamin E or intermediate doses of carotenoids showed significant changes in ex vivo LDL oxidizability, total plasma peroxide concentrations and urinary 8-oxo-7,8-dihydro-2(')-deoxyguanosine excretion. Patients on chronic hemodialysis present with oxidative stress in the presence of normal vitamin E but impaired vitamin C status and, due to anemia, need to be treated with parenteral iron. We studied the effects of a single oral dose of vitamin E taken 6 h prior to intravenous infusion of 100 mg iron, which exceeded the iron-binding capacity of transferrin. Vitamin E significantly reduced and in combination with a single dose of vitamin C completely abrogated acute oxidative stress induced by the iron load. Patients with cystic fibrosis are exposed to chronic oxidative stress due to an overproduction of reactive oxygen species as a result of neutrophil-dominated lung inflammation and impaired antioxidant status. Biochemical vitamin E and carotenoid deficiencies could be fully corrected even in the presence of fat malabsorption using intermediate doses of either RRR alpha-tocopherol or all-rac alpha-tocopheryl acetate and water-miscible all-trans beta-carotene. Long-term supplementation reduced ex vivo LDL oxidizability, in vivo lipid peroxidation and lung inflammation.
Institute of Molecular Biology, Biochemistry and Microbiology (IMBM), University of Graz, Austria. brigitte.winklhoferroob@uni-graz.at
Brigitte M
BM
Winklhofer-Roob
Edmond
E
Rock
Josep
J
Ribalta
David H
DH
Shmerling
Johannes M
JM
Roob
D000375:Aging; D002338:Carotenoids / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000097:blood / Q000378:metabolism; D019587:Dietary Supplements; D006304:Health Status; D006801:Humans; D007275:Injections, Intravenous; D007501:Iron / Q000008:administration & dosage / Q000097:blood; D018384:Oxidative Stress / Q000187:drug effects*; D006435:Renal Dialysis / Q000009:adverse effects; D014810:Vitamin E / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use*; D014811:Vitamin E Deficiency / Q000209:etiology / Q000517:prevention & control*
D014810:Vitamin E; D002338:Carotenoids; D007501:Iron