Oxidative Stress in Normal‐Weight Obese Syndrome

The normal‐weight obese (NWO) syndrome was identified in women whose body weight (BW) and BMI are normal but whose fat mass (FM) is >30%. In these subjects, an early inflammatory status has been demonstrated. The aim was to verify whether oxidative stress occurs in NWO. Sixty age‐matched white Italian women were studied and subdivided as follows: 20 normal‐weight individuals (NW) (BMI <25 kg/m²; FM% <30%); 20 NWO (BMI <25 kg/m²; FM% >30%); 20 preobese‐obese (OB) (BMI >25 kg/m²; FM% >30%). Anthropometric, body composition (by dual‐energy X‐ray absorptiometry) variables, plasma levels of some cytokines, reduced glutathione (GSH), lipid hydroperoxide (LOOH), nitric oxide (NO) metabolites (NO₂^?/NO₃^?), antioxidant nonproteic capacity (ANPC) were measured and compared between groups. Glucose and lipid metabolism parameters were assessed. GSH and NO₂^?/NO₃^? levels resulted lower in OB and NWO compared to NW (P < 0.01). LOOH levels resulted higher in OB and NWO (P < 0.01). ANPC in NWO was lower than NW but higher with respect to OB (P < 0.01). Correlation analysis revealed strong associations between GSH levels and BW, BMI, FM% (R = ?0.45, at least P < 0.05); waist circumference (W) (R = ?0.33, P < 0.05); FFM% (R = 0.45, P < 0.01); IL‐1α, IL‐6, IL‐10, IL‐15 (R = ?0.39, ?0.33, ?0.36 ?0.34, respectively, P < 0.05); triglycerides (R = ?0.416, P < 0.05). LOOH levels were negatively related to FFM% (R = ?0.413, P < 0.05) and positively to FM%, IL‐15, TNF‐α, insulin, total cholesterol, low‐density lipoprotein cholesterol, and triglycerides (R = 0.408, R = 0.502, R = 0.341, R = 0.412, R = 0.4036, R = 0.405, R = 0.405, respectively, P < 0.05). The study clearly indicates that NWO, besides being in early inflammatory status, are contextually exposed to an oxidative stress related to metabolic abnormalities occurring in obesity.