Normal endothelial function after meals rich in olive or safflower oil previously used for deep frying.
OBJECTIVE
Polyunsaturated fats are more susceptible to oxidation during heating than monounsaturated fats but their effects on endothelial function when heated are unknown. The aim of this study was to compare the effect of meals rich in heat-modified safflower and olive oils on postprandial flow-mediated endothelium-dependent dilation (EDD) in healthy men.


RESULTS
Flow-mediated EDD and glyceryltrinitrate-induced endothelium-independent dilation of the brachial artery were investigated in 14 subjects before and 4 hours after meals rich in olive oil and safflower oil used hourly for deep-frying for 8 hours in a double-blind crossover study design. There were high levels of lipid oxidation products (peroxides and carbonyls) in both heated oils. Plasma triglycerides were markedly increased at 4 hours after heated olive oil (1.26 +/- 0.43 vs 2.06 +/- 0.97 mmol/L) and heated safflower oil (1.44 +/- 0.63 vs 1.99 +/- 0.88 mmol/L). There was no change in EDD between fasting and postprandial studies and the response during the postprandial period was not significantly (p = 0.51) different between the meals (heated olive oil: 4.9 +/- 2.2% vs 4.9 +/- 2.5%; heated safflower oil: 5.1 +/- 3.1% vs 5.6 +/- 3.4%).


CONCLUSIONS
Meals rich in olive and safflower oils previously used for deep frying and containing high levels of lipid oxidation products increase postprandial serum triglycerides without affecting endothelial function. These findings suggest that relatively short-term use of these vegetable oils for frying may not adversely affect postprandial endothelial function when foods containing the heat-modified oils are consumed.
Williams
M J
MJ
Department of Medicine, Dunedin School of Medicine, University of Otago, 201 Great King Street, Dunedin, New Zealand.
Sutherland
W H
WH
McCormick
M P
MP
Yeoman
D
D
de Jong
S A
SA
Walker
R J
RJ
D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D001916:Brachial Artery / Q000502:physiology; D008076:Cholesterol, HDL / Q000097:blood; D018592:Cross-Over Studies; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage* / Q000097:blood; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D000069463:Olive Oil; D010938:Plant Oils / Q000008:administration & dosage* / Q000378:metabolism; D019518:Postprandial Period; D012450:Safflower Oil / Q000008:administration & dosage* / Q000097:blood; D014280:Triglycerides / Q000097:blood
D008076:Cholesterol, HDL; D004042:Dietary Fats, Unsaturated; D000069463:Olive Oil; D010938:Plant Oils; D014280:Triglycerides; D012450:Safflower Oil