Effect on lipoprotein profile of replacing butter with margarine in a low fat diet: randomised crossover study with hypercholesterolaemic subjects

Objective: To examine the effect on lipid and lipoprotein concentrations when butter or an unsaturated margarine is used for cooking or spreading in a reduced fat diet. Design: Randomised crossover study with two intervention periods of six weeks9 duration separated by a five week washout. Setting: Community setting in New Zealand. Subjects: 49 volunteers with polygenic hypercholesterolaemia and baseline total cholesterol concentration in the range 5.5-7.9 mmol/l. Main outcome measures: Concentrations of total and low density lipoprotein, Lp(a) lipoprotein, high density lipoprotein, apolipoprotein B 100, and apolipoprotein AI. Results: Concentrations of low density lipoprotein cholesterol and apolipoprotein B were about 10% lower with margarine than with butter. Lp(a) lipoprotein and high density lipoprotein cholesterol concentrations were similar with the two diets. Conclusion: Despite concerns about adverse effects on lipoproteins of trans fatty acids in margarines, the use of unsaturated margarine rather than butter by hypercholesterolaemic people is associated with a lipoprotein profile that would be expected to reduce cardiovascular risk. Key messages Key messages These findings suggest that the relatively small amounts of trans fatty acids that are typically present in unsaturated margarine have no adverse effects on lipid and lipoprotein concentrations The effects of unsaturated margarine on oxidation of low density lipoproteins are still to be examined Nevertheless, unsaturated margarine seems to be an appropriate substitute for saturated fat in diets recommended to people with hyperlipidaemia