Diet high in monounsaturated fat does not have a different effect on arterial elasticity than a low-fat, high-carbohydrate diet

Objective To compare the effects of a modified-fat diet high in monounsaturated fat, and a low-fat/high-carbohydrate diet on arterial elasticity. Design Randomized crossover design; each diet period was 1 month and a 2-week wash out period occurred in between. Subjects/setting Thirty healthy, free-living, nonsmoking men and women were recruited from the Melbourne, Australia, metropolitan region of Australia. Men were aged 35 to 55 years and postmenopausal women were aged 50 to 60 years and were not taking hormone replacement therapy. Twenty-eight subjects completed the study. Intervention Two diets of equal energy value: a modified-fat diet and a low-fat/high-carbohydrate diet; the modified-fat diet had 3 times more energy from monounsaturated fat. Main outcome measures Arterial elasticity and serum lipoprotein concentrations. Statistical analysis The general linear model was used to investigate overall effect and any carryover or order effects. Paired t test and the general linear model were used to compare the results from the 2 diet periods. Results High-density lipoprotein cholesterol concentration was significantly higher on the modified-fat diet than on the low-fat/low-carbohydrate diet. Arterial elasticity and concentrations of total cholesterol, low-density lipoprotein cholesterol, and triglycerides were not significantly different on the 2 diets. Applications/conclusions There is no evidence to favor a diet high in monounsaturated fat over a low-fat/high-carbohydrate diet because of an effect on arterial elasticity. Other changes in diet may be needed to cause a beneficial effect on arterial elasticity.