Cholesterolaemic influence of palmitic acid in the sn-1, 3 v. the sn-2 position with high or low dietary linoleic acid in healthy young men.
Healthy young men were fed four diets for 2 weeks each providing natural fats containing palmitic acid (16 : 0) predominantly in the sn-1, 3 position of dietary TAG or containing 16 : 0 predominantly in the sn-2 position with low or high levels of linoleic acid (18 : 2n-6). Two treatments supplied 16 : 0 in the sn-1, 3 positions from palmstearin with low (3 % energy) or high (>7 % energy) 18 : 2n-6 and two treatments supplied 16 : 0 in the sn-2 position from lard with high or low levels of 18 : 2n-6. Diets contained 30-35 % energy as fat, 7-11 % energy as 16 : 0 and moderate levels of cholesterol. Fasting serum cholesterol and lipoprotein concentrations were measured. Cholesterol fractional synthesis rate (FSR) was determined by 2H incorporation. Diets providing 16 : 0 in the sn-2 position resulted in lower fasting serum total cholesterol (TC) and a lower TC:HDL ratio than diets providing 16 : 0 in the sn-1, 3 positions. Diets with high levels of 18 : 2n-6 significantly decreased the TC:HDL ratio, reaffirming the well-known cholesterol-reducing effect of 18 : 2n-6. A lower non-esterified cholesterol FSR was observed with low dietary levels of 18 : 2n-6. No differences between dietary treatments were found for serum HDL-cholesterol, LDL-cholesterol or TAG. It is concluded that dietary fats containing 16 : 0 in the sn-2 position may result in slightly lower fasting TC than diets providing 16 : 0 in the sn-1, 3 positions, while the level of n-6 polyunsaturated fat influences endogenous cholesterol synthesis.
Forsythe
C E
CE
Alberta Institute for Human Nutrition, Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Canada.
French
M A
MA
Goh
Y K
YK
Clandinin
M T
MT
D000328:Adult; D002784:Cholesterol / Q000097:blood*; D002791:Cholesterol, Dietary / Q000008:administration & dosage; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage* / Q000032:analysis; D002149:Energy Intake / Q000502:physiology; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D006801:Humans; D019787:Linoleic Acid / Q000008:administration & dosage* / Q000737:chemistry; D008055:Lipids / Q000097:blood; D008074:Lipoproteins / Q000097:blood; D008297:Male; D019308:Palmitic Acid / Q000008:administration & dosage* / Q000737:chemistry
D002791:Cholesterol, Dietary; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D004041:Dietary Fats; D004791:Enzyme Inhibitors; D008055:Lipids; D008074:Lipoproteins; C030104:lipoprotein cholesterol; D019308:Palmitic Acid; D002784:Cholesterol; D019787:Linoleic Acid; C029310:lard