Inflammatory and Oxidative Stress Markers Related to Adherence to the Mediterranean Diet in Patients with Metabolic Syndrome

Metabolic syndrome (MetS) is characterized by increased pro-oxidative stress and a pro-inflammatory state. Several studies emphasized the protective effect of the Mediterranean dietary pattern (MDP). To assess the oxidative and inflammatory state according to the adherence to MDP using biomarkers in patients with MetS. Antioxidant and pro-inflammatory biomarkers were determined in plasma, peripheral blood mononuclear cells (PBMCs), and neutrophils of adults (aged 55–75 years old; 60% women) with MetS living in Mallorca (Spain). Anthropometrics, dietary intake by a validated semi-quantitative 143-item food frequency questionnaire, and a Dietary Inflammatory Index were measured. Patients with low adherence to MDP showed higher levels of glycated haemoglobin A1c and triglycerides, and lower levels of HDL cholesterol. Plasma levels of interleukin-1β, IL-6, IL-15, tumour necrosis factor α, xanthine oxidase, and ghrelin, and activities of superoxide dismutase, and myeloperoxidase were higher in subjects with low adherence to the MDP. Reactive oxygen species production in PBMCs and neutrophils stimulated with lipopolysaccharide was higher in participants with low adherence to the MDP. Patients with MetS and higher adherence to the MDP showed less altered anthropometric parameters, blood biochemical profile, and better oxidative and inflammatory status.