Effects of exchanging 4%en between dietary stearic and palmitic acid on hamster plasma lipoprotein metabolism.

This study was designed to determine whether the exchange of specific fatty acids (palmitic (16:0) for stearic (18:0)), would exert differential effects on plasma and lipoprotein lipids, when diets contained approximately 30%en from fat with adequate levels of linoleic acid (18:2). Thirty-two male Golden Syrian hamsters were fed isocaloric purified diets with comparable amounts of 18:2 (approximately 10.5%en). The 18:0-rich diet (50% cocoa butter, 41% safflower oil, 9% sunflower oil) provided 4.8%en 16:0 and 5.3%en from 18:0, while the 16:0-rich diet (59% palm oil, 36% safflower oil, 5% olive oil) provided 8.7%en from 16:0 and 1.2%en from 18:0, resulting in a 16:0/18:0 exchange of approximately 4%en. Both diets contained negligible amounts of lauric and myristic acid (< 0.2%en), approximately 9.5%en from oleic acid and 77 mg cholesterol/1000 kcal. Animals were fed their respective diets for 4 weeks at which point various lipid and lipoprotein parameters were measured. There were no significant difference between dietary groups for any of the measured parameters, which included body weights, food consumption, plasma lipids, lipoprotein lipid and apoprotein concentrations, as well as lipoprotein compositions. Additionally, estimated diameters of various lipoprotein particles were not affected by the fatty acid exchanges employed. Thus these data suggest that when total fat is restricted to 30%en and 18:2 levels are approximately 10%en, a 4%en exchange between 16:0 and 18:0 (representing intakes of approximately 9 g/d/2000 kcal diet) produces comparable plasma lipids.