Journal Name:
Am. J. Clin. Nutr.
Article Title:
Fatty acid composition of serum cholesterol esters, and erythrocyte and platelet membranes as indicators of long-term adherence to fat-modified diets.
Date Written:
1994
Volume:
59
Number:
2
Page:
364
Author(s):
Sarkkinen, E.S.; Agren, J.J.; Ahola, I.; Ovaskainen, M.L.; Uusitupa, M.I.
Article:
Longer term intervention studies for cholesterol lowering often suffer from problems with subject adherence to intervention diets. Research has shown that the proportion of linoleic acid in cholesterol esters (CEs) or erythrocyte (ER) and platelet (PT) membranes correlates well with the amount of dietary linoleic acid (LA omega 6), as well as with dietary polyunsaturated fatty acids (PUFA) and the ratio of polyunsaturated to saturated fatty acids (P:S). A positive association between the percentage of energy from oleic acid and monounsaturated fatty acids (MUFA) and the proportion of oleic acid in plasma lipids has also been demonstrated in both population and experimental studies. The proportion of saturated fatty acids (SFA) in serum lipids has been found to be high following the consumption of a diet high in saturated fats. The objective of this study was to correlate the fatty acid composition of serum CEs, ERs, and PT as biomarkers of adherence following four different fat-modified diets: 1) high-saturated fat -35/14:10:4 (% of energy from total/ saturated:monounsaturated:polyunsaturatcd fatty acids in the actual diet) 2) AHA (American Heart Association) type-32/ 10:8:8 3) monoene-enriched with canola oil - 34/11:11:5, or 4) low-fat-30/ 12:8:3.
Diets were fed for 6 months to 160 hypercholesterolemic subjects in a parallel design. The results showed that the fatty acid composition of CBs, ERs, and PT reflected the patterns of fatty acid intake. In the AHA-type group, an increase in the proportion of LA was found. No significant increase in the proportion of oleic acid or other MUFA in the monoene-enriched group was found. This is probably due to the moderate amount of monoenes compared with those studies in which a high intake of MUFA has been seen as elevated proportions of oleic acid in CEs or ERs. The proportions of SFA and PUFA in the CEs, ERs, and PTs did not differ between the high-SFA and low-fat diets with unaltered fatty acid composition. Decreases in the proportions of palmitic acid in CEs were found in the AHA-type and monoene-enriched-diet groups. The differences in the proportions of palmitic acid in CEs and LA and palmitoleic acids in PT were significant in the AHA-type and monoene-enriched-diet groups compared with the high-SFA group. An increase in alpha-linolenic acid in CEs was an indicator of the use of canola oil, which was the main source of monoenes in the monoene-enriched-diet group.
In this study, differences in fatty acid concentrations in CEs, ERs, and N’s were related to the differences in dietary intake. In conclusion, a decrease in the proportion of palmitic acid in CEs reflected reduced intake of SFA in the AHA-type and monoene-enriched groups and an increased proportion of LA reflected an increased intake of LA in the AHA-type group. A moderate increase in the amount of MUFA in the diet did not change the fatty acid composition of serum CEs, ERs, or PT, but an increased intake of canola oil resulted in an elevated proportion of alpha-linolenic acid in biomarkers.
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