Postprandial Endothelial Function: The Effect of Various Types of Fat and of Red Wine Intake on Flow- Mediated Dilation in Healthy Volunteers

Background : Current evidence suggests that postprandial lipid composition may have either atherogenic or anti-atherogenic properties. This study investigated the acute postprandial effect of three different types of fat (saturated, mono-unsaturated, poly-unsaturated) and of red wine upon endothelial function of healthy subjects. Methods: We fed 21 healthy young subjects four meals containing 1000 kcal and 50 g fat each. Three of the meals contained different fat sources: yellow cheese (saturated fat-meal A), olive oil (monounsaturated fat-meal B) and margarine (polyunsaturated fat-meal C). The fourth meal contained the same amount of saturated fat as the first one together with 250 cc of red wine (meal D). We measured serum lipoproteins, with the use of standard laboratory techniques. Β rachial artery flow-mediated vasodilation (FMD), an index of endothelial function, was also assessed with B-Mode vascular ultrasound. All measurements were performed before, 2 and 4 h after each meal Results: All four meals significantly raised plasma triglycerides. Meal A was associated with a decrease in FMD 2 and 4 hours after its intake ( 16.5 ± 5% vs. 13 ± 4% vs. 12.3 ± 6% , p= 0.030) while with meal D FMD profoundly decreased 2 hours postprandially with a rapid return to baseline levels at 4 hours (14.3 ± 9.5 vs. 8.6 ± 5.5 vs. 12.6 ± 7.5 , p=0.214) . This type of response was associated with a concomitant increase of basal brachial artery diameter at 2 hours postpandially ( 3.7±0.6 mm vs 4.2±0.7 mm vs 3.9±0.7mm at 0, 2 and 4 hours respectively , p=0.000 ). Meals B and C did not significantly affect FMD. Conclusions. Saturated fat acutely decreases FMD while mono-unsaturated and poly-unsaturated fat do not have any harmful effect on endothelium. The concomitant intake of red wine with saturated fat is associated with a delayed counteracting effect on lipid-induced postprandial endothelial dysfunction.