Is there an interplay between adherence to Mediterranean diet, antioxidant status and vascular disease in atrial fibrillation patients?

Mediterranean Diet (Med-Diet) is associated with reduced incidence of vascular events (VEs) in atrial fibrillation (AF), but the mechanism accounting for its beneficial effect is only partially known. We hypothesized that Med-Diet may reduce VEs by improving antioxidant status, as assessed by glutathione peroxidase 3 (GPx3) and superoxide dismutase (SOD). We performed a prospective cohort study investigating the relationship between adherence to Med-Diet, serum baseline GPx3 and SOD activities, and the occurrence of vascular events (VEs) in 690 AF patients. GPx3 activity was directly associated with Med-Diet score (B=0.192, p<0.001) and inversely with age (B=-0.124, p=0.001), after adjustment for potential confounders; Med-Diet weakly affected SOD levels. During a mean follow-up of 46.1±28.2 months, 89 VEs were recorded; patients with VEs had lower GPx3 levels compared to those without (p=0.002); no differences regarding SOD activity were found. Multivariable Cox regression analysis showed that age (Hazard ratio [HR]:1.065, p<0.001), logGPx3 (above median, HR:0.629, p<0.05) and Med-Diet score (HR:0.547, p<0.05) predicted VEs. Med-Diet favourably modulates antioxidant activity of GPx3 in AF resulting in reduced VEs rate. We hypothesize that modulating GPx3 levels by Med-Diet could represent an additional nutritional strategy to prevent VEs in AF patients.