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The Effects of Dietary Fatty Acids On Lipoprotein Lipase Activity and Gene Expression.

Brooks, Catriona. (1998) The Effects of Dietary Fatty Acids On Lipoprotein Lipase Activity and Gene Expression. Doctoral thesis, University of Surrey (United Kingdom)..

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Abstract

An exaggerated postprandial lipaemic response has long been implicated as a risk factor for coronary heart disease (CHD). The extent and duration of this postprandial response is regulated by lipoprotein lipase (LPL). It is also known that the fatty-acid composition of the diet can affect LPL activity. In this study, we therefore hypothesised that chronic dietary intakes of n-3 polyunsaturated fatty acids (n-3 PUFA) and monounsaturated fatty acids (MUFA) would modulate LPL activity, possibly by influencing gene expression. The objective of the 2 dietary intervention studies performed was to determine the feasibility of increasing dietary n-3 PUFA and MUFA intakes using fatty acid-modified, commercially produced foods in a free-living environment. The first study was a 3-week trial in which 9 middle-aged male volunteers consumed a variety of eicosapentaenoic acid (EPA)- and docosahexaenoic acid (DHA)-enriched foods. The second study was a 2-month trial in which 43 male volunteers increased their dietary MUFA (oleic acid) intake by replacing saturates, using olive oil-enriched foods. Significant increases in EPA+DHA (P < 0. 001) and oleic-acid (P < 0. 001) intakes were observed and the quality of the foods was excellent. These findings support the use of fatty acid-modified foods as a suitable vehicle through which to achieve changes in dietary composition. Few effects on postprandial lipid metabolism were found as a result of altering intakes of n-3 PUFA or MUFA. This suggests that adaptive responses to modified diets develop over a longer period of time than was investigated here. However, a significant reduction in plasma total cholesterol (P < 0. 02) and LDL cholesterol (P < 0. 001) concentrations was observed following substitution of MUFA for saturated fatty acids. Therefore, MUFA-enriched diets are a suitable alternative to low-fat, high-carbohydrate diets as a means of reducing plasma cholesterol levels and CHD risk. There is strong evidence that dietary fatty acids affect adipose-tissue LPL activity; however, to date it is unclear whether these effects are substrate or hormone driven. To investigate if the effect is substrate specific, a sensitive competitive RT-PCR method was developed. Although no significant changes in LPL gene expression or LPL activity were observed, there was a trend for the gene expression values to be higher following the n-3 PUFA and MUFA diets.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors : Brooks, Catriona.
Date : 1998
Additional Information : Thesis (Ph.D.)--University of Surrey (United Kingdom), 1998.
Depositing User : EPrints Services
Date Deposited : 24 Apr 2020 15:27
Last Modified : 24 Apr 2020 15:27
URI: http://epubs.surrey.ac.uk/id/eprint/855118

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