Abstract
Studies have shown that dietary fat saturation affects guinea pig plasma low density lipoprotein (LDL) levels by altering both LDL receptor-mediated catabolism and flux rates of LDL (Fernandez et al. 1992. J. Lipid Res. 33: 97-109). The present studies investigated whether saturated fatty acids of varying chain lengths have differential effects on LDL metabolism. Guinea pigs were fed 15% (w/w, 35% calories) fat diets containing either palm kernel oil (PK), 52% lauric acid/18% myristic acid; palm oil (PO), 43% palmitic acid/4% stearic acid; or beef tallow (BT), 23% palmitic acid/14% stearic acid. Plasma LDL cholesterol levels were significantly higher for animals fed the PK diet (P < 0.001) with values of 83 +/- 19 (n = 12), 53 +/- 8 (n = 12) and 44 +/- 16 (n = 10) mg/dl for PK, PO, and BT diets, respectively. The relative percentage composition of LDL was modified by fat type; however, LDL diameters and peak densities were not different between diets, indicating no effect of saturated fatty acid composition on LDL size. ApoB/E receptor-mediated LDL fractional catabolic rates (FCR) were significantly lower in animals fed the PK diet (P < 0.01) and LDL apoB flux rates were reduced (P < 0.01) in animals fed the BT diet. A correlation was found between plasma LDL levels and receptor-mediated LDL catabolism (r = -0.66, P < 0.01). A higher apoB/E receptor number (Bmax), determined by in vitro LDL binding to guinea pig hepatic membranes, was observed for animals fed BT versus PK or PO diets and Bmax values were significantly correlated with plasma LDL levels (r = -0.776, P < 0.001). These results indicate that saturated fatty acids of varying chain length have differential effects on hepatic apoB/E receptor expression and on LDL apoB flux rates which in part account for differences in plasma LDL cholesterol levels of guinea pigs fed these saturated fats.
Highlights
Studies have shown that dietary fat saturation affects guinea Pig Plasma low density lipoprotein (LDL) levels by altering both LDL receptor-mediated catabolism and flux rates of LDL
I These results indicate that saturated fatty acids of varying chain length have differential effects on hepatic apoB/E receptor expression and on LDL apoB flux rates which in part account for differences in plasma LDL cholesterol levels of guinea pigs fed these saturated fats.- Fernandez, M
As has been previously reported for guinea pigs (11-13), changes in plasma total cholesterol levels mediated by dietary fatty acids occur mainly in LDL and a parallel increase in plasma LDL was observed in animals fed the palm kernel oil (PK) diet compared to the other two dietary fat groups (Table 3)
Summary
Studies have shown that dietary fat saturation affects guinea Pig Plasma low density lipoprotein (LDL) levels by altering both LDL receptor-mediated catabolism and flux rates of LDL I These results indicate that saturated fatty acids of varying chain length have differential effects on hepatic apoB/E receptor expression and on LDL apoB flux rates which in part account for differences in plasma LDL cholesterol levels of guinea pigs fed these saturated fats.- Fernandez, M. 33: Supplementary key words apoB/E receptor apoLDL fractional catabolic rate dietary fatty acids apoLDL flux rates varying in chain length from 10 to 18 carbons, recent data indicate that individual saturated fattv acids can have specific, and in some cases opposite, effects on plasma cholesterol levels (2-8). Spady, and Dietschy (8) reported that lauric, myristic, and palmitic acids increased plasma LDL cholesterol levels in hamsters compared to animals fed stearic acid by decreasing LDL apoB/E receptor activity and increasing LDL production rates. High dietary intakes of saturated fatty acids have been imp1icated as a causative factor in the high incidence Of hypercholesterolemia and increased risk for atherosclerosis and cardiovascular disease which exist in many
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
