Impact of hydrogenated fat consumption on endogenous cholesterol synthesis and susceptibility of low-density lipoprotein to oxidation in moderately hypercholesterolemic individuals.
The effects of replacing corn oil with corn oil margarine in stick form on endogenous cholesterol synthesis and susceptibility of low-density lipoprotein (LDL) to oxidation were assessed in 14 middle-aged and elderly men and women aged 63 +/- 12 years (mean +/- SD) with moderate hypercholesterolemia (mean LDL-cholesterol [LDL-C], 4.24 +/- 0.59 mmol/L at the time of recruitment). Subjects consumed each of two diets for 32-day periods, one enriched in corn oil, which contained 30% of energy as fat (7% saturated fatty acid [SFA], 9% monounsaturated fatty acid [MUFA] [0.4% 18:1n9 trans], and 11% polyunsaturated fatty acid [PUFA]) and 85 mg cholesterol/4.2 MJ, and one enriched in stick corn oil margarine, which contained 30% fat (8% SFA, 12% MUFA [4.2% 18:1n9trans], and 8% PUFA) and 77 mg cholesterol/4.2 MJ. Both diets were isocaloric and supplied by a metabolic research kitchen. Mean total cholesterol levels were lowest (P = .039) when subjects consumed the corn oil-enriched diet (5.01 +/- 0.51 mmol/L) as compared with the margarine-enriched diet (5.30 +/- 0.58 mmol/L). LDL-C levels were 3.24 +/- 0.51 and 3.50 +/- 0.54 mmol/L when subjects consumed corn oil-and margarine-enriched diets, respectively (P = .058). There were no significant differences in high-density lipoprotein cholesterol (HDL-C) or triglyceride concentrations between the two experimental periods. Consumption of the margarine-enriched diet versus the corn oil-enriched diet tended to result in lower cholesterol fractional synthetic rates ([C-FSRs] 0.0466 +/- 0.0175 and 0.0668 +/- 0.0298, respectively, P = .080) and cholesterol absolute synthetic rates ([C-ASRs] 1.1761 +/- 0.5375 and 1.6954 +/- 0.8685, respectively, P = .092); however, differences did not reach statistical significance. Consumption of the margarine-enriched diet versus the corn oil-enriched diet resulted in a significantly higher concentration of alpha-tocopherol in both plasma and LDL(P = .004 and P = .011, respectively). LDL particle size tended to be smaller after subjects consumed the margarine-enriched diet versus the corn oil-enriched diet (P = .103). Susceptibility of LDL to oxidation was similar after consumption of the corn oil- and margarine-enriched diets. These data suggest that an increased rate of endogenous cholesterol synthesis did not contribute to the higher plasma cholesterol concentrations during the period when subjects consumed the margarine-enriched diet. Therefore, the increase in cholesterol concentration resulting from margarine consumption was likely attributable, at least in part, to a decreased catabolic rate of cholesterol. Additionally, susceptibility of LDL to in vitro oxidation was not altered by consumption of hydrogenated fat.
Cuchel
M
M
Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, MA, USA.
Schwab
U S
US
Jones
P J
PJ
Vogel
S
S
Lammi-Keefe
C
C
Li
Z
Z
Ordovas
J
J
McNamara
J R
JR
Schaefer
E J
EJ
Lichtenstein
A H
AH
D000293:Adolescent; D000328:Adult; D008078:Cholesterol, LDL / Q000378:metabolism; D003314:Corn Oil / Q000378:metabolism; D004041:Dietary Fats / Q000008:administration & dosage*; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000378:metabolism*; D050356:Lipid Metabolism; D008077:Lipoproteins, LDL / Q000378:metabolism*; D008297:Male; D008383:Margarine; D010084:Oxidation-Reduction
D008078:Cholesterol, LDL; D004041:Dietary Fats; D005227:Fatty Acids; D008077:Lipoproteins, LDL; D003314:Corn Oil; D008383:Margarine