Docosahexaenoic Acid Content in Plasma Phospholipids and Desaturase Indices in Obese Children

Abstract

AIMS: In obesity, fatty acid composition is altered with reduced docosahexaenoic acid (DHA) levels. Desaturating enzymes, stearoyl-CoA desaturase (SCD), delta-6 desaturase (D6D) and delta-5 desaturase (D5D) modulate fatty acid composition and are thus associated with the development of metabolic syndrome. The aim of this study was to identify the relationships among DHA content, desaturase indices and the components of metabolic syndrome in childhood obesity. METHODS: Thirty-two obese children (27 male, 5 female) aged 12.0±2.6 years (mean±SD), with a relative body weight greater than 120% of the standard weight for sex, age and height, were recruited. Fatty acid composition of plasma phospholipids was analyzed by gas chromatography, and the desaturase indices were assessed: SCD (16:1n-7/16:0 and 18:1n-9/18:0), D6D (20:3n-6/18:2n-6) and D5D (20:4n-6/20:3n-6). RESULTS: No sex difference was observed in fatty acid composition. DHA content tended to have an inverse association with body mass index (BMI) (r=-0.337, p=0.0592), and correlated significantly with very low-density lipoprotein-triglyceride (r=-0.558, p=0.0057). In addition, DHA content had significant negative relationships with SCD indices (SCD16; r=-0.373, p=0.0357 and SCD18; r=-0.580, p=0.0005), which correlated positively with BMI(r=0.439, p=0.0120, r=0.353, p=0.0473, respectively), but had no association with D5D or D6D. CONCLUSIONS: DHA content in obese children was independent of the desaturation of alpha-linolenic acid. Reduced DHA content was associated with increased SCD index, and might contribute to the development of metabolic syndrome. Dietary management including fatty acids is suggested to be important to prevent and better manage obesity.