Oxidative Stress and Antioxidant Levels in Patients with Anorexia Nervosa after Oral Re-alimentation: A Systematic Review and Exploratory Meta-analysis

Oxidative stress markers seem to be higher in patients with anorexia nervosa (AN) than healthy controls, but the potentially beneficial effects of weight gain is not known. We calculated random effects standardised mean differences (SMDs) as effect size measures of oxidative stress marker changes after re-alimentation reported in two or more studies, summarising others descriptively. Seven longitudinal studies (n = 104) were included. After a median follow-up period of 8 weeks, AN patients significantly increased their body mass index (15.1 ± 2.1 to 17.1 ± 2.2, p < 0.0001). This weight gain was followed by a significant increase in serum levels of the antioxidant albumin (studies = 6, SMD = 0.50, 95%CI = 0.18; 0.82, p = 0.002; I(2) = 16%) and a significant decrease in the oxidative stress marker Apolipoprotein B (studies = 2, n = 19, SMD = -0.85, 95%CI = -1.53; -0.17, p = 0.01; I(2) = 0). In one study, catalase and total antioxidant capacity increased, whilst superoxide dismutase significantly decreased. In conclusion, oral re-alimentation, even without full-weight normalisation, seems to improve oxidative stress in people with AN.