Both consuming plant sterols and exercising have been shown to affect blood cholesterol levels on their own, they note in last month's issue of the American Journal of Clinical Nutrition.
"Our research is the first to look at the complementary combined effects of these therapies," said senior author Peter Jones.
The researchers from McGill university recruited 74 non-active individuals between the ages of 40 and 70 and divided them into four different groups: combination (consumed margarine containing plant sterols and exercised), exercise (consumed plant-sterol -free margarine and exercised), sterol only (consumed margarine containing plant sterols and did not exercise) and control (consumed plant-sterol free margarine and did not exercise).
Exercise involved using stair-stepping machines and stationary bicycles three times a week. The subjects were asked to consume margarine four times a day for eight weeks. The researchers analysed blood samples and lipids.
"In comparison with plant sterols or exercise alone, the combination of plant sterols and exercise yielded the most beneficial change in the volunteer's cholesterol and lipid levels," said lead author and McGill doctoral student, Krista Varady.
"This combination therapy favourably altered their lipid profiles by decreasing total cholesterol, low-density lipoprotein (LDL) cholesterol, and triacylglycerol levels and by increasing high-density lipoprotein (HDL) cholesterol levels."
Jones added that there were other benefits associated with the exercise programme.
"Our volunteers were typically inactive. In addition to the altered cholesterol levels, the increased physical activity contributed to loss of weight and improved motivation. Long term exercise can also reduce blood pressure and reduce the risk of other health complications."