Could a high-fat diet rich in unsaturated fatty acids impair the cardiovascular system?

BACKGROUND: Dyslipidemia results from consumption of a diet rich in saturated fatty acids and is usually associated with cardiovascular disease. A diet rich in unsaturated fatty acids is usually associated with improved cardiovascular condition.
OBJECTIVE: To investigate whether a high-fat diet rich in unsaturated fatty acids (U-HFD) - in which fatty acid represents approximately 45% of the total calories - impairs the cardiovascular system.
METHODS: Male, 30-day-old Wistar rats were fed a standard (control) diet or a U-HFD containing 83% unsaturated fatty acid for 19 weeks. The in vivo electrocardiogram, the spectral analysis of heart rate variability, and the vascular reactivity responses to phenylephrine, acetylcholine, noradrenaline and prazosin in aortic ring preparations were analyzed to assess the cardiovascular parameters.
RESULTS: After 19 weeks, the U-HFD rats had increased total body fat, baseline glucose levels and feed efficiency compared with control rats. However, the final body weight, systolic blood pressure, area under the curve for glucose, calorie intake and heart weight⁄final body weight ratio were similar between the groups. In addition, both groups demonstrated no alteration in the electrocardiogram or cardiac sympathetic parameters. There was no difference in the responses to acetylcholine or the maximal contractile response of the thoracic aorta to phenylephrine between groups, but the concentration necessary to produce 50% of maximal response showed a decrease in the sensitivity to phenylephrine in U-HFD rats. The cumulative concentration- effect curve for noradrenaline in the presence of prazosin was shifted similarly in both groups.
CONCLUSIONS: The present work shows that U-HFD did not impair the cardiovascular parameters analyzed.