Introduction: Obesity is a chronic disease associated with oxidative stress. Bariatric surgery for the treatment of obesity may affect biomarkers of oxidative stress.
Objectives: The aim of the present study was to evaluate the effect of Roux-en-Y gastric bypass (RYGB) on blood markers of oxidative stress, such as vitamins C and E, β-carotene, reduced glutathione (GSH), catalase (CAT), ferric reducing antioxidant potential (FRAP), and thiobarbituric acid-reactive substances (TBARS).
Methods: A prospective controlled clinical trial was carried out. The participants were distributed into two groups: a control group (n=35), which was evaluated once, and a bariatric group (n=35), which was evaluated at baseline as well as 6, 12, and 24 months after surgery.
Results: After surgery, the BMI decreased from 47.05±1.46 to 30.53±1.14 kg/m (P<0.001), but 25.7% of the participants regained weight after 24 months. In relation to the baseline, postsurgery reductions were found in vitamin C (31.9±4.6%, P<0.001), β-carotene (360.7±368.3%, P<0.001), vitamin E (22.8±4.1%, P<0.001), GSH (6.6±5.2%, P=0.090), CAT (12.7±5.6%, P=0.029), and FRAP (1.2±3.8%, P=0.085) 2 years after RYGB. TBARS levels decreased after 12 months (71.6±2.9%, P<0.001) in relation to the baseline but increased by 195.0±28.2% between the 12th and the 24th month (P<0.001).
Conclusion: The present findings show that oxidative stress returned 2 years after RYGB. Concentrations of vitamin C, β-carotene, GSH, CAT, and FRAP were decreased, whereas the concentration of TBARS decreased in the first year but increased in the following year, which may be partly explained by the imbalance between antioxidants and pro-oxidants.