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/m(2); FM% <30%); 20 NWO (BMI <25 kg/m(2); FM% >30%); 20 preobese-obese (OB) (BMI >25 kg/m(2); 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 (NO(2)(-)/NO(3)(-)), antioxidant nonproteic capacity (ANPC) were measured and compared between groups. Glucose and lipid metabolism parameters were assessed. GSH and NO(2)(-)/NO(3)(-) 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.