title: Characteristics of obese children with low content of arachidonic acid in plasma lipids.
abstract: BACKGROUND
  Although there have been many studies on the relationship between obesity and long-chain polyunsaturated fatty acid (LCPUFA), the results and their interpretation are controversial, especially in children. Arachidonic acid (AA), the product of n-6 LCPUFA, is reported to be related to insulin resistance. The purpose of the present paper was to investigate the LCPUFA profile in obese children and mechanisms that contribute to reduced AA content.
  
  
  METHODS
  An age- and sex-matched control study was performed. The study subjects were 59 obese children (mean age, 11.8 years) and 53 healthy non-obese children (mean age, 12.5 years). The study parameters included anthropometric measurements, serum lipids, leptin and fatty acid composition in plasma.
  
  
  RESULTS
  Plasma fatty acids in obese children had lower linoleic acid (P < 0.0001) and higher dihomo-gamma-linolenic acid (P = 0.0004) than those in non-obese children. In all subjects combined, delta-6 desaturase (D6D) index (ratios of [C 18:3n-6+C 20:2n-6]/C 20:4n-6 or C 20:4n-6/C 18: 2n-6) correlated with leptin (P < 0.0001). There was no significant difference in AA content between obese and non-obese. However, the AA content was low (<mean - 1SD in controls) in 27.1% of obese children, in whom D6D index was not elevated in spite of high insulin concentration.
  
  
  CONCLUSIONS
  Obese children had changes in plasma LCPUFA profile that indicate upregulation of n-6 LCPUFA metabolism, probably caused by activated D6D activity to compensate AA demand. Heterogeneity of AA content in obese children depends on D6D and delta-5-desaturase activity, which may reflect insulin sensitivity.
authors.affiliation: Department of Pediatrics, Nihon University School of Medicine, Tokyo, Japan. tomokada@med.nihon-u.ac.jp
authors.forename: Tomoo
authors.initials: T
authors.lastname: Okada
authors.forename: Noriko F
authors.initials: NF
authors.lastname: Sato
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kuromori
authors.forename: Michio
authors.initials: M
authors.lastname: Miyashita
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tanigutchi
authors.forename: Fujihiko
authors.initials: F
authors.lastname: Iwata
authors.forename: Mitsuhiko
authors.initials: M
authors.lastname: Hara
authors.forename: Mamoru
authors.initials: M
authors.lastname: Ayusawa
authors.forename: Kensuke
authors.initials: K
authors.lastname: Harada
authors.forename: Emiko
authors.initials: E
authors.lastname: Saito
mesh_terms: D016718:Arachidonic Acid / Q000097:blood*; D002648:Child; D005227:Fatty Acids / Q000097:blood; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood*
chemical_list: D005227:Fatty Acids; D008055:Lipids; D016718:Arachidonic Acid