Plasma fatty acids as predictors of glycaemia and type 2 diabetes.

AIMS/HYPOTHESIS: Our aim was to investigate the fasting proportions of fatty acids and estimated desaturase and elongase activities in three different lipid fractions in plasma, phospholipids (PLs), cholesteryl esters (CEs) and triacylglycerols (TGs), as predictors for the worsening of glycaemia (area under the glucose curve in an OGTT [glucose AUC]) and incident type 2 diabetes in a 5.9 year follow-up of the Metabolic Syndrome in Men population-based cohort. METHODS: Fatty acid proportions were measured in plasma PL, CE and TG fractions in 1,364 Finnish men aged 45-68 years at baseline. The prospective follow-up study included only men who were non-diabetic at baseline and had data available at follow-up (n = 1,302). A total of 71 participants developed new type 2 diabetes during follow-up. RESULTS: After adjusting for confounding factors, total saturated fatty acids, palmitoleic acid (16:1n-7), dihomo-γ-linolenic acid (20:3n-6) and estimated stearoyl-CoA desaturase 1 and Δ(6)-desaturase (D6D) enzyme activities significantly predicted the worsening of glycaemia whereas total polyunsaturated fatty acid, linoleic acid (18:2n-6) and elongase activity predicted a decrease in the glucose AUC. Estimated D6D activity and dihomo-γ-linolenic acid (20:3n-6) were associated with an increased risk of incident type 2 diabetes. Results were consistent across the three different lipid fractions. However, fatty acid proportions in the PL and CE fractions were stronger predictors for glycaemia and incident type 2 diabetes compared with fatty acid proportions in the TG fraction. CONCLUSIONS/INTERPRETATION: Selected fatty acid proportions of plasma lipid fractions and their ratios, which reflect desaturase and elongase enzyme activities, may be good biomarkers for the worsening of glycaemia and incident type 2 diabetes.