Impaired endothelial function following a meal rich in used cooking fat

OBJECTIVES The purpose of this study was to test the hypothesis that intake of used cooking fat is associated with impaired endothelial function. BACKGROUND Diets containing high levels of lipid oxidation products may acc elerate atherogenesis, but the effect on endothelial function is unknown. METHODS Flow-mediated endothelium-dependent dilation and glyceryl trinitrat e-induced endothelium-independent dilation of the brachial artery were inve stigated in 10 men. Subjects had arterial studies before and 4 h after thre e test meals: 1) a meal (fat 64.4 g) rich in cooking fat that had been used for deep frying in a fast food restaurant; 2) the same meal (fat 64.4 g) r ich in unused cooking fat, and 3) a corresponding low fat meal (fat 18.3 g) without added fat. RESULTS Endothelium-dependent dilation decreased between fasting and postpr andial studies after the used fat meal (5.9 +/- 2.3% vs. 0.8 +/- 2.2%, p = 0.0003), but there was no significant change after the unused fat meal (5.3 +/- 2.1% vs. 6.0 +/- 2.5%) or low fat meal (5.3 +/- 2.3% vs. 5.4 +/- 3.3%) . There was no significant difference in endothelium-independent dilation a fter any of the meals. Plasma free fatty acid concentration did not change significantly during an), of the meals. The level of postprandial hypertrig lyceridemia was not associated with change in endothelial function. CONCLUSIONS Ingestion of a meal rich in fat previously used for deep frying in a commercial fast food restaurant resulted in impaired arterial endothe lial function. These findings suggest that intake of degradation products o f heated fat contribute to endothelial dysfunction. (J Am Coil Cardiol 1999 ;33:1050-5) (C) 1999 by the American College of Cardiology.