Compositions comprising high concentration of monounsaturated fatty acids having low melting points and high iodine values and use of such compositions as dietary supplements, nutraceuticals or pharmaceuticals for reducing atherosclerotic plaque in mammals. It has been found that high concentrations of monounsaturated fatty acids (MUFAs) having low melting point temperatures and iodine values of about 50 to about 130 can be used to effectively treat atherosclerosis. Epidemiological studies suggest that those populations consuming large quantities of C18:1 found in olive oil are protected against vascular diseases such as atherosclerosis.
