Effects of monounsaturated enriched sunflower oil on CHD risk factors including LDL size and copper-induced LDL oxidation

Objective: To compare the effects of a diet high in monounsaturated enriche d sunflower oil and a low fat diet on CHD risk factors including in vitro C u-induced LDL oxidation and LDL size, lipids, lipoproteins, glucose and ins ulin. Design: A randomized crossover dietary intervention. Setting: Free living individuals. Subjects: Fourteen healthy males 35 to 55 years of age and 14 healthy postm enopausal women 50 to 60 years of age completed the dietary intervention. T wo subjects did not complete the study, and their data were not included. Interventions: A low fat, high carbohydrate diet (22% to 25% of energy from total fat, 7% to 8% of energy from monounsaturated fat and 55% to 60% of e nergy from carbohydrate) was compared to a monounsaturated enriched sunflow er oil (MO) diet (40% to 42% of energy from fat, with 26% to 28% from monou nsaturated fat and 40% to 45% of energy from carbohydrate) in an isocaloric substitution. Each dietary period was one month. Results: Total cholesterol, LDL cholesterol, triglycerides and glucose were not significantly different between the two diets. HDL cholesterol, HDL3 c holesterol and insulin were significantly higher on the MO diet, mean 7%, 7 % and 17% higher respectively. Copper-induced LDL oxidation lag phase was s ignificantly longer (mean 18%) after the MO diet compared to the low fat, h igh carbohydrate diet. LDL particle size was not significantly different. Conclusions: The significant increase in LDL oxidation lag phase and the si gnificantly higher HDL cholesterol on the MO diet would be expected to be a ssociated with a decrease in CHD risk.