RESUMO
BACKGROUND: Roux-en-Y gastric bypass (RYGB) is effective for weight loss but may have long-term effects on markers of oxidative stress (OS). The objective of this study is to evaluate the effect of bariatric surgery with RYGB on OS blood markers in a 72-month period after surgery. METHODS: A prospective cohort study was conducted with 20 patients before and after RYGB (months M0, M6, M12, M24, and M72) compared with a control group of 35 adults assessed only once. RESULTS: The body mass index (BMI) (45.71 ± 6.97 kg/m2) decreased by 38% from M0 to M24 (17.51 ± 5.50 kg/m2, p < 0.001), followed by a 12% increase from M24 to M72 (p < 0.001). Serum concentrations of vitamin E (adjusted for total cholesterol and triglycerides) and vitamin C increased throughout the study (p < 0.001). ß-carotene levels decreased progressively through to M72 (p = 0.008). Reduced glutathione (GSH) content and catalase (CAT) activity decreased at M6, M12, and M24, but no differences were found at M72 compared with M0. Concentrations of thiobarbituric acid reactive substances (TBARS) were lower M12 and M24 in comparison with baseline values (p < 0.001 and p = 0.004, respectively) but were similar to baseline values at 72 months (p = 0.114). CONCLUSIONS: GSH content, TBARS concentrations, and CAT activity returned to baseline values 72 months after RYGB, indicating the persistence of systemic OS, possibly attributable to weight regain and/or changes in the antioxidant defenses, such as the reduction in ß-carotene levels.