Effects of lycopene supplementation on oxidative stress and markers of endothelial function in healthy men

Objective: The objective was to determine the effects of lycopene supplementation on endothelial function assessed by reactive hyperemia peripheral arterial tonometry (RH-PAT) and oxidative stress. Methods: Healthy men (n = 126) were randomized to receive placebo (n = 38), 6 mg (n = 41), or 15 mg (n = 37) lycopene daily for 8-week. Results: Serumlycopene increased in a dose-dependent manner after 8-week supplementation (P < 0.001). The 15 mg/day group had greater increase in plasma SOD activity (P = 0.014) and reduction in lymphocyte DNA comet tail length (P = 0.042) than the placebo group. Intragroup comparison revealed a 23% increase in RH-PAT index from baseline (1.45 +/- 0.09 vs. 1.79 +/- 0.12; P = 0.032) in the 15 mg/day group after 8-week. hs-CRP, systolic blood pressure, sICAM-1 and sVCAM-1 significantly decreased, and beta-carotene and LDL-particle size significantly increased only in the 15 mg/day group. Interestingly, the beneficial effect of lycopene supplementation on endothelial function (i.e., RH-PAT and sVCAM-1) were remarkable in subjects with relatively impaired endothelial cell function at initial level. Changes in RH-PAT index correlated with SOD activity (r = 0.234, P = 0.017) especially in the 15mg lycopene/day group (r = 0.485, P = 0.003), lymphocyte DNA comet tail moment (r = -0.318, P = 0.001), and hs-CRP (r = -0.238, P = 0.011). In addition, changes in lycopene correlated with hs-CRP (r = -0.230, P = 0.016) and SOD activity (r = 0.205, P = 0.037). Conclusion: An increase in serum lycopene after supplementation can reduce oxidative stress which may play a role in endothelial function. (C) 2010 Elsevier Ireland Ltd. All rights reserved.