The Serum Selenium Level, the Activity of Some Selenodependent Enzymes and the Lipid Profile in Childhood Obesity

Oxidative stress and dyslipidemia are present in childhood obesity. Selenoproteins are important antioxidants. Glutathione peroxidase and thioredoxin reduce the level of peroxides while the conversion of the tyroid hormon T4 to T3 needs also a selenoenzyme. Selenium deficiency can reduce the selenoproteins activity. The aim of this study was to determine the serum: selenium (Se), thioredoxin level (Trx) and activity of glutathione peroxidase (GPx) in obese children with dysmetabolism. The lipid profile, the hormones (free T4 and TSH), serum Se, serum Trx and GPx activity and atherogenic indexes (TG/HDLc, total cholesterol/HDLc, apoB/apoA-I ) were determined in 20 healthy children (10-16 years old) versus 41 overweight/obese children, same age, in an observational study. Spectro-photometer and ELISA methods were used. The GPx activity and the serum Se level had similar values in the studied groups , while the serum Trx level was lower in the obese children. The GPx activity was positively correlated with atherogenic indexes, negatively correlated with apo A-I (r= -0.74) and Se was positively correlated with apo B (r=0.52). The obese children had TSH and freeT4 in the normal range, but freeT4 was significantly higher in comparison with the values observed in the normal weight children. In conclusion, in childhood obesity, the normal serum range values for selenium or for selenium dependent proteins can hide a dysmetabolism of selenium because there are significant differences for the values of these parameters versus the ones from normal weight children. In childhood obesity, serum GPx activity and selenium values were strongly correlated with the atherogenic indexes.