title: Postprandial lipaemia induces an acute decrease of insulin sensitivity in healthy men independently of plasma NEFA levels.
abstract: OBJECTIVE
  Typical Western diets cause postprandial lipaemia for 18 h per day. We tested the hypothesis that postprandial lipaemia decreases insulin sensitivity.
  
  
  METHODS
  Employing a randomised crossover design, we administered two types of virtually isocaloric meals to ten healthy volunteers on two separate occasions. The meals (Meals 1 and 2) were both designed to produce a rise in triglycerides, but only Meal 1 generated a rise in NEFA, too. Insulin sensitivity, as quantified by an IVGTT with minimal model analysis, was calculated postabsorptively at 08.00 h and postprandially at 13.00 h, i.e. 3 h after meal ingestion.
  
  
  RESULTS
  Triglycerides rose from 0.91+/-0.31 mmol/l postabsorptively to 2.08+/-0.70 mmol/l postprandially with Meal 1 (p=0.005) and from 0.92+/-0.41 to 1.71+/-0.79 mmol/l with Meal 2 (p=0.005). Neither the triglyceride levels at 13.00 h, nor the post-meal AUCs for triglycerides were statistically different between Meal 1 and Meal 2. NEFA rose from 0.44+/-0.17 mmol/l postabsorptively to 0.69+/-0.16 mmol/l postprandially with Meal 1 (p=0.005) and showed no significant change with Meal 2 (0.46+/-0.31 mmol/l postabsorptively vs 0.36+/-0.32 mmol/l postprandially, p=0.09). Both the NEFA level at 13.00 h and the post-meal AUC for NEFA were significantly higher after Meal 1 than Meal 2. Compared with the postabsorptive state, insulin sensitivity decreased postprandially after each of the two meals to a comparable degree (Meal 1: -53%, p=0.02; Meal 2: -45%, p=0.005).
  
  
  CONCLUSIONS
  Our study reveals a drop in insulin sensitivity during postprandial lipaemia and strongly suggests that decreased insulin sensitivity is brought about by elevated plasma levels of triglyceride-rich lipoproteins independently of plasma NEFA levels.
authors.affiliation: Clinical Department of Internal Medicine, Medical University of Innsbruck, Anichstrasse 35, A-6020, Innsbruck, Austria. michael.pedrini@uibk.ac.at
authors.forename: M T
authors.initials: MT
authors.lastname: Pedrini
authors.forename: A
authors.initials: A
authors.lastname: Niederwanger
authors.forename: M
authors.initials: M
authors.lastname: Kranebitter
authors.forename: C
authors.initials: C
authors.lastname: Tautermann
authors.forename: C
authors.initials: C
authors.lastname: Ciardi
authors.forename: T
authors.initials: T
authors.lastname: Tatarczyk
authors.forename: J R
authors.initials: JR
authors.lastname: Patsch
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D018592:Cross-Over Studies; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D005951:Glucose Tolerance Test; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood / Q000150:complications*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D019518:Postprandial Period; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D014280:Triglycerides