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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #122652
Title: DEGREE OF HYDROGENATION AFFECTS TRIGLYCERIDE CLEARANCE AND CHOLESTEROL ESTERIFICATION RATES IN MODERATELY HYPERCHOLESTEROLEMIC WOMEN

Author
item MATTHAN, NIRUPTA - HNRCA
item CIANFLONE, KATHERINE - MCGILL U, CANADA
item LICHTENSTEIN, ALICE - HNRCA
item AUSMAN, LYNNE - HNRCA
item JAUHIAINEN, MATTI - NA. PUB HLT INST, FINLAND
item JONES, PETER - MCGILL U, CANADA

Submitted to: Journal of Lipid Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/2001
Publication Date: 11/1/2001
Citation: MATTHAN, N.R., CIANFLONE, K., LICHTENSTEIN, A.H., AUSMAN, L.M., JAUHIAINEN, M., JONES, P.J. DEGREE OF HYDROGENATION AFFECTS TRIGLYCERIDE CLEARANCE AND CHOLESTEROL ESTERIFICATION RATES IN MODERATELY HYPERCHOLESTEROLEMIC WOMEN. JOURNAL OF LIPID RESEARCH. 2001;42:1841-8.

Interpretive Summary: Numerous studies have evaluated the negative health effects of trans fatty acids or hydrogenated fats on plasma lipid and lipoprotein levels, but the actual mechanisms responsible for these changes remain unclear. Potential mechanisms include alterations in triglyceride clearance and cholesterol esterification rates. Consequently, these parameters were evaluated in subjects who consumed different forms of hydrogenated fats with varying trans and polyunsaturated fatty acid levels. Results demonstrate for the first time that alterations in the acylation stimulating protein pathway, which regulates triglyceride clearance and synthesis by adipose tissue, are associated with increases in circulating cholesterol levels. The decrease in levels of the cardioprotective lipoprotein HDL, which is a characteristic feature of high trans fatty acid intake are possibly related to a reduction in esterification rates of newly synthesized cholesterol. Given that current dietary heart disease risk reduction guidelines encourage substitution of vegetable oils and its products like margarines for those of animal origin, we feel that our findings have implications for dietary recommendations. These include the substitution of unhydrogenated oil and softer margarines for not only saturated fat but also harder margarines in processed foods.

Technical Abstract: To determine whether the rates of triglycerides (TG) clearance and esterification of newly synthesized cholesterol (ER) are influenced by different forms of hydrogenated fats, 14 women (65-71 yrs) consumed each of 5 diets for 5 week periods according to a randomized crossover design. The experimental diets contained 55% energy as carbohydrate, 15% as protein and 30% as fat. 2/3 of the fat was provided by either soybean oil (SO), squeeze (SQM), tub (TM), or stick (SM) margarines or butter (BT). Esterification rates of newly synthesized cholesterol were determined using the deuterium incorporation method, TG clearance was determined by measuring key components of the acylation stimulating protein (ASP) pathway; plasma ASP, free fatty acids (FFA), glucose and insulin levels. Plasma ASP were lowest (p<0.05) on the SM (33.4 +/-12.7 nmol.L-1) compared to the SO (48.7 +/-17.0 nmol.L-1) and SQM (50.7 +/-15.7 nmol.L-1) diets. FFA were highest (p<0.05) on the SM diet (0.86 +/-0.45 mmol.L-1) relative to all the other diets. ER was lowest (p<0.05) after the SM (0.111 +/- 0.062 p.p-1) diet and highest after consumption of the SQM (0.216 +/-0.123 p.p-1) diet. ASP levels were negatively correlated with FFA (r=-0.63, p<0.05), while FFA was positively correlated with apo B (r=0.42, p<0.05) and VLDL-C (r=0.58, p<0.05), and negatively correlated with HDL-C (r=- 0.51, p<0.05). ER was positively correlate with HDL-C and HDL2 subfraction (r=0.53 and 0.45, p<0.05). These data demonstrate that the increases in circulating cholesterol levels, observed with consumption of hydrogenated fat rich diets can be explained by alterations in ASP pathway activity. The decrease in HDL-C levels seen with SM consumption could be related to reduction in esterification rates of newly synthesized cholesterol.