title: Adipose tissue palmitoleic acid and obesity in humans: does it behave as a lipokine?
abstract: BACKGROUND
  Animal models have shown that adipose-derived palmitoleic acid may serve as a lipokine that contributes to resistance to diet-induced obesity. Studies in humans have evaluated only plasma palmitoleic acid concentrations, which reflect stearoyl-coenzyme A desaturase 1 (SCD1) activity in the liver and are associated with increased risk of obesity. These apparent opposite effects of palmitoleic acid deserve further research in humans. Because carbohydrate intake can increase hepatic SCD1 activity, it could be used as a stratifying variable to disentangle the effects of adipose tissue SCD1 compared with the effects of liver SCD1 activity on obesity.
  
  
  OBJECTIVE
  We examined whether the effects of adipose tissue palmitoleic acid and SCD1 activity were associated with decreased obesity prevalence and whether this association was modified by carbohydrate intake.
  
  
  METHODS
  Prevalence ratios (PRs) of obesity [body mass index (in kg/m²) > 30] were examined in a cross-sectional study in 1926 adults in Costa Rica. Two desaturation indexes (16:1/16:0 and 18:1/18:0) were used as surrogate measures of adipose tissue SCD1 activity.
  
  
  RESULTS
  We observed a positive association between adipose tissue palmitoleic acid concentrations and obesity (PR for lowest compared with highest quintiles of palmitoleic acid: 2.27; 95% CI: 1.52, 3.38; P for trend < 0.0001). A significant association was also observed between obesity and adipose desaturation indexes. The association between adipose tissue palmitoleic acid concentrations and obesity was attenuated in persons with low carbohydrate intake.
  
  
  CONCLUSIONS
  There is no direct evidence that adipose tissue palmitoleic acid behaves as a lipokine to reduce obesity occurrence in humans. However, the attenuation of the association by low carbohydrate intake warrants further research on adipose-derived palmitoleic acid and obesity risk.
authors.affiliation: Department of Community Health, Brown University, Providence, RI, USA.
authors.forename: Jian
authors.initials: J
authors.lastname: Gong
authors.forename: Hannia
authors.initials: H
authors.lastname: Campos
authors.forename: Stephen
authors.initials: S
authors.lastname: McGarvey
authors.forename: Zhijin
authors.initials: Z
authors.lastname: Wu
authors.forename: Robert
authors.initials: R
authors.lastname: Goldberg
authors.forename: Ana
authors.initials: A
authors.lastname: Baylin
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism*; D005260:Female; D006801:Humans; D008099:Liver / Q000201:enzymology; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000209:etiology / Q000378:metabolism*; D013230:Stearoyl-CoA Desaturase / Q000378:metabolism
chemical_list: D005229:Fatty Acids, Monounsaturated; C008757:palmitoleic acid; C523776:SCD1 protein, human; D013230:Stearoyl-CoA Desaturase