Effect of surgical weight loss on free radical and antioxidant balance:: A preliminary report

Background: This study observes the effect of surgical weight loss on free radical and antioxidant vitamin balance. Patients and Methods: 22 consecutive morbidly obese patients undergoing vertical banded gastroplasty (VBG) were chosen for the study. Postoperative studies were done at 12 and 24 weeks. Plasma antioxidant and vitamin determinations were performed by HPLC method. Results: Subjects lost a significant amount of weight (P<0.01). Compared to preoperative measurements, postoperative measurements of plasma betacarotene were not statististically different both at 12 and 24 weeks (13.86±1.26 μg/dl, 12.35±1.2, P=0.44; 14.33±2.03, P=0.77; preoperatively, 12 and 24 weeks respectively). Alpha-tocopherol increased slightly at the 12th week; the difference was not significant (8.50±0.77; 9.56±0.82, P=0.37; preoperatively and 12th week respectively). The levels of alpha-tocopherol rose at 24th week significantly (10.89±0.55, P=0.028). The indicator of lipid peroxidation (malondialdehyde) decreased with weight loss (1.505±0.11 μmol/L preoperatively; 0.75±0.062 at 12th week, P=0.01; 0.712±0.05 at 24th week, P<0.01). Conclusion: Our data show that free radical generation falls markedly in association with weight loss after VBG. Surgical weight loss leads to significant decrease in oxidant production and also leads to increase in some antioxidant vitamins. The demonstration of decreased free radical generation and correction of balance between free radicals and antioxidant vitamins has important implications for oxidative mechanisms underlying obesity-associated disorders.