Background: Palmitoleic acid (16:1n-7) is a product of endogenous lipogenesis. In human obesity, 16:1n-7 is reported to correlate with indexes of adiposity and insulin concentrations.
Objective: We investigated the relation between adiposity, especially in the abdominal region, and plasma monounsaturated fatty acid (MUFA) profiles in obese children.
Design: A case-control study was performed. The study subjects were 59 obese children (x +/- SD age: 11.8 +/- 3.8 y) and 53 age- and sex-matched healthy, nonobese children (aged 12.5 +/- 0.5 y). The study's variables included anthropometric measurements, serum lipids, leptin, and fatty acid composition in plasma.
Results: MUFA profiles of obese subjects showed a significantly higher content of 16:1n-7, 18:1n-9, and 20:1n-9 and significantly higher stearoyl-CoA desaturase (SCD) activity (ratio of 16:1n-7 to 16:0) than in nonobese controls. In a multiple regression analysis, percentage body fat, waist-to-height ratio, and waist-to-hip ratio (WHR) were significant determinants of 16:1n-7 content. SCD activity had a positive, significant correlation with leptin. However, in a multiple regression analysis that included percentage body fat, WHR, and leptin as independent determinants, WHR was the only determinant of SCD activity.
Conclusions: Plasma 16:1n-7 content has a significant relation with abdominal adiposity in obese children. This change in the MUFA profile may be caused by activation of SCD that is not sufficiently suppressed by leptin. Endogenous lipogenesis may be an important factor in the pathogenesis of obesity in children.