Self-report of fruit and vegetable intake that meets the 5 a day recommendation is associated with reduced levels of oxidative stress biomarkers and increased levels of antioxidant defense in premenopausal women.

BACKGROUND: Oxidative stress has been associated with a variety of chronic diseases and reproductive disorders. Fruits and vegetables (F/V) may contribute to antioxidant vitamin and micronutrient levels and reduce oxidative stress.
OBJECTIVE: To investigate the effect of meeting the 5 A Day For Better Health Program recommendation for F/V consumption on biomarkers of oxidative damage and antioxidant defense.
DESIGN: In this longitudinal study, healthy premenopausal women (n=258) were followed for ≤2 menstrual cycles with ≤16 oxidative stress measures timed to cycle phase. MAIN OUTCOME MEASURES: Plasma concentrations of F2-isoprostane, 9-hydroxyoctadecadieneoic acid, 13-hydroxyoctadecadieneoic acid, erythrocyte activity of superoxide dismutase, glutathione reductase, and glutathione peroxidase, as well as blood micronutrient concentrations were measured. Dietary intake was assessed by food frequency questionnaires (FFQs) (1 per cycle), and 24-hour recalls (≤4 per cycle). STATISTICAL ANALYSES PERFORMED: Fruit and vegetable servings were dichotomized based on the recommendation to consume five servings of F/V each day. Linear mixed models with repeated measures were used to analyze lipid peroxidation markers, antioxidant vitamins, and antioxidant enzymes by cycle phase and in association with usual F/V intake.
RESULTS: For both 24-hour recall (timed to cycle phase) and cycle-specific FFQ, meeting the recommendation to consume five servings of F/V each day was associated with decreased F2-isoprostanes (24-hour recall β=-.10 [95% CI, -0.12 to -0.07]; FFQ β= -.14 [95% CI, -0.18 to -0.11]). Glutathione reductase was lower in association with typical consumption of five or more servings of F/V by FFQ but not in the phase-specific analysis. Higher levels of ascorbic acid, lutein, beta carotene, and beta cryptoxanthin were observed with both intake measures.
CONCLUSIONS: Meeting the 5 A Day For Better Health Program recommendation was associated with lower oxidative stress and improved antioxidant status in analyses of typical diet (via FFQ) and in menstrual cycle phase-specific analyses using 24-hour recalls. Green salads were commonly eaten and increasing intake of salads may be a useful strategy to influence oxidation in reproductive aged women.