Antioxidant supplementation does not attenuate oxidative stress at high altitude

Andrew W. Subudhi, Kevin A. Jacobs, Todd A. Hagobian, Jill A. Fattor, Charles S. Fulco, Stephen R. Muza, Paul B. Rock, Andrew R. Hoffman, Allen Cymerman, Anne L. Friedlander

    Research output: Contribution to journalArticlepeer-review

    50 Scopus citations

    Abstract

    Introduction: Hypobaric hypoxia and heightened metabolic rate increase free radical production. Purpose: We tested the hypothesis that antioxidant supplementation would reduce oxidative stress associated with increased energy expenditure (negative energy balance) at high altitude (HA 4300 m). Methods: For 12 d at sea level (SL), 18 active men were fed a weight-stabilizing diet. Testing included fasting blood and 24-h urine samples to assess antioxidant status [plasma α-tocopherol, β-carotene, lipid hydroperoxides (LPO), and urinary 8-hydroxydeoxyguanosine (8-OHdG)] and a prolonged submaximal (55% V̇o2peak) oxidative stress index test (OSI) to evaluate exercise-induced oxidative stress (plasma LPO, whole blood reduced and oxidized glutathione, glutathione peroxidase, and urinary 8-OHdG). Subjects were then matched and randomly assigned to either a placebo or antioxidant supplement group for a double-blinded trial. Supplementation (20,000 IU of β-carotene, 400 IU α-tocopherol acetate, 500 mg ascorbic acid, 100 μg selenium, and 30 mg zinc, or placebo) was begun 3 wk prior to and throughout a 14-d HA intervention. At HA, subjects' daily energy intake and expenditure were adjusted to achieve a caloric deficit of approximately 1400 kcal. Fasting blood and 24-h urine samples were collected throughout HA and the OSI test was repeated on H A day 1 and day 13. Results: Resting LPO concentrations increased and urinary 8-OHdG concentrations decreased over HA with no effect of supplementation. Prolonged submaximal exercise was not associated with increased concentrations of oxidative stress markers at SL or HA. Conclusions: Antioxidant supplementation did not significantly affect markers of oxidative stress associated with increased energy expenditure at HA.

    Original languageEnglish
    Pages (from-to)881-888
    Number of pages8
    JournalAviation Space and Environmental Medicine
    Volume75
    Issue number10
    StatePublished - Oct 2004

    Keywords

    • DNA damage
    • Free radical
    • Glutathione
    • Hypoxia
    • Lipid peroxidation

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