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Antioxidant nutrient supplementation and brachial reactivity in patients with coronary artery disease.

Abstract

Epidemiologic studies have shown a correlation between antioxidant intake and coronary artery disease (CAD); however, the results of clinical trials have been inconsistent. We evaluated the effect of combined antioxidant supplementation on endothelial function and its correlation with change in low-density lipoprotein cholesterol (LDLC) oxidation in patients with established CAD. In a double-blind, placebo-controlled 12-week trial, 18 nonsmoking, nondiabetic patients (mean age 62.4 +/- 8.1 years) were randomized to receive placebo or antioxidant supplementation consisting of (a) 400 IU of vitamin E, 500 mg of vitamin C, and 12 mg of beta-carotene; or (b) 800 IU of vitamin E, 1000 mg of vitamin C, and 24 mg of beta-carotene daily. Endothelial function was evaluated on the basis of percent and absolute changes in brachial artery diameter in response to reactive hyperemia induced by occlusion-release. Baseline and 12-week values of LDL oxidation (measured on the basis of lag phase), endothelial function, dietary composition, serum antioxidants, and lipids were measured. We noted a significant between-group difference at 12 weeks for change in plasma concentrations of alpha-tocopherol, vitamin C, and beta-carotene between the placebo and antioxidant groups (p <.05). Both placebo and treatment groups demonstrated a significant improvement in lag phase; however, the treatment group achieved a greater, although nonsignificant, magnitude of change compared with the placebo group (181.3 +/- 177.8 minutes vs 80.6 +/- 63.0 minutes, P =.06). Within-group change in brachial reactivity from baseline to follow-up in the treatment group did not reach statistical significance (1.7% +/- 3.2% and 0.07 mm +/- 0.13 mm, P =.08 and P =.09, respectively), whereas an improved change in brachial reactivity was observed in the placebo group (2.2% +/- 1.9%, 0.09 mm +/- 0.06 mm, P <.05). No significant correlation was found between change in lag phase and change in endothelial function. On adjustment for confounders, antioxidant supplementation was found not to be a significant predictor of brachial reactivity. We conclude that antioxidant supplementation did not significantly alter brachial reactivity, despite significantly increased plasma levels of antioxidants and improved lag phase. These data should be confirmed in larger-scale trials and examined in studies evaluating individual dietary antioxidant supplementation.

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  • Authors+Show Affiliations

    ,

    Department of Internal Medicine, Division of Cardiology, University of Michigan Medical Center, Ann Arbor, MI, USA.

    ,

    Source

    MeSH

    Antioxidants
    Ascorbic Acid
    Brachial Artery
    Constriction
    Coronary Disease
    Diet
    Dietary Supplements
    Double-Blind Method
    Endothelium, Vascular
    Hemorheology
    Humans
    Lipid Peroxidation
    Lipids
    Lipoproteins, LDL
    Placebos
    Vasodilation
    Vitamin E
    alpha-Tocopherol
    beta Carotene

    Pub Type(s)

    Clinical Trial
    Journal Article
    Randomized Controlled Trial

    Language

    eng

    PubMed ID

    11944023

    Citation

    McKechnie, Ronald, et al. "Antioxidant Nutrient Supplementation and Brachial Reactivity in Patients With Coronary Artery Disease." The Journal of Laboratory and Clinical Medicine, vol. 139, no. 3, 2002, pp. 133-9.
    McKechnie R, Rubenfire M, Mosca L. Antioxidant nutrient supplementation and brachial reactivity in patients with coronary artery disease. J Lab Clin Med. 2002;139(3):133-9.
    McKechnie, R., Rubenfire, M., & Mosca, L. (2002). Antioxidant nutrient supplementation and brachial reactivity in patients with coronary artery disease. The Journal of Laboratory and Clinical Medicine, 139(3), pp. 133-9.
    McKechnie R, Rubenfire M, Mosca L. Antioxidant Nutrient Supplementation and Brachial Reactivity in Patients With Coronary Artery Disease. J Lab Clin Med. 2002;139(3):133-9. PubMed PMID: 11944023.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Antioxidant nutrient supplementation and brachial reactivity in patients with coronary artery disease. AU - McKechnie,Ronald, AU - Rubenfire,Melvyn, AU - Mosca,Lori, PY - 2002/4/11/pubmed PY - 2002/5/1/medline PY - 2002/4/11/entrez SP - 133 EP - 9 JF - The Journal of laboratory and clinical medicine JO - J. Lab. Clin. Med. VL - 139 IS - 3 N2 - Epidemiologic studies have shown a correlation between antioxidant intake and coronary artery disease (CAD); however, the results of clinical trials have been inconsistent. We evaluated the effect of combined antioxidant supplementation on endothelial function and its correlation with change in low-density lipoprotein cholesterol (LDLC) oxidation in patients with established CAD. In a double-blind, placebo-controlled 12-week trial, 18 nonsmoking, nondiabetic patients (mean age 62.4 +/- 8.1 years) were randomized to receive placebo or antioxidant supplementation consisting of (a) 400 IU of vitamin E, 500 mg of vitamin C, and 12 mg of beta-carotene; or (b) 800 IU of vitamin E, 1000 mg of vitamin C, and 24 mg of beta-carotene daily. Endothelial function was evaluated on the basis of percent and absolute changes in brachial artery diameter in response to reactive hyperemia induced by occlusion-release. Baseline and 12-week values of LDL oxidation (measured on the basis of lag phase), endothelial function, dietary composition, serum antioxidants, and lipids were measured. We noted a significant between-group difference at 12 weeks for change in plasma concentrations of alpha-tocopherol, vitamin C, and beta-carotene between the placebo and antioxidant groups (p <.05). Both placebo and treatment groups demonstrated a significant improvement in lag phase; however, the treatment group achieved a greater, although nonsignificant, magnitude of change compared with the placebo group (181.3 +/- 177.8 minutes vs 80.6 +/- 63.0 minutes, P =.06). Within-group change in brachial reactivity from baseline to follow-up in the treatment group did not reach statistical significance (1.7% +/- 3.2% and 0.07 mm +/- 0.13 mm, P =.08 and P =.09, respectively), whereas an improved change in brachial reactivity was observed in the placebo group (2.2% +/- 1.9%, 0.09 mm +/- 0.06 mm, P <.05). No significant correlation was found between change in lag phase and change in endothelial function. On adjustment for confounders, antioxidant supplementation was found not to be a significant predictor of brachial reactivity. We conclude that antioxidant supplementation did not significantly alter brachial reactivity, despite significantly increased plasma levels of antioxidants and improved lag phase. These data should be confirmed in larger-scale trials and examined in studies evaluating individual dietary antioxidant supplementation. SN - 0022-2143 UR - https://www.unboundmedicine.com/medline/citation/11944023/Antioxidant_nutrient_supplementation_and_brachial_reactivity_in_patients_with_coronary_artery_disease_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022214302533576 DB - PRIME DP - Unbound Medicine ER -