A saturated fatty acid-rich diet induces an obesity-linked proinflammatory gene expression profile in adipose tissue of subjects at risk of metabolic syndrome

Background: Changes in dietary fat composition could lower the risk of developing metabolic syndrome. Adipose tissue is an interesting tissue in this respect because of its role in lipid metabolism and inflammation. Objective: Our objective was to investigate the effect of a saturated fatty acid (SFA)– and a monounsaturated fatty acid (MUFA)–rich diet on insulin sensitivity, serum lipids, and gene expression profiles of adipose tissue in subjects at risk of metabolic syndrome. Design: A parallel controlled-feeding trial was conducted in 20 abdominally overweight subjects. Subjects received an SFA diet or an MUFA diet for 8 wk. Plasma and subcutaneous adipose tissue samples were obtained, and insulin sensitivity was measured by using a hyperinsulinemic-euglycemic clamp. Adipose tissue samples underwent whole-genome microarray and histologic analysis. Plasma and adipose tissue fatty acid composition and concentrations of serum cholesterol and plasma cytokine were determined. Results: Consumption of the SFA diet resulted in increased expression of genes involved in inflammation processes in adipose tissue, without changes in morphology or insulin sensitivity. The MUFA diet led to a more antiinflammatory gene expression profile, which was accompanied by a decrease in serum LDL-cholesterol concentrations and an increase in plasma and adipose tissue oleic acid content. Conclusions: Consumption of an SFA diet resulted in a proinflammatory "obesity-linked" gene expression profile, whereas consumption of an MUFA diet caused a more antiinflammatory profile. This suggests that replacement of dietary SFA with MUFA could prevent adipose tissue inflammation and may reduce the risk of inflammation-related diseases such as metabolic syndrome. This trial was registered at clinicaltrials.gov as NCT00405197.