The effect of dietary oleic, linoleic, and linolenic acids on fat oxidation and energy expenditure in healthy men

January 1, 2008 Human Health and Nutrition Data 0 Comments

The effect of dietary oleic, linoleic, and linolenic acids on fat oxidation and energy expenditure in healthy men

Year: 2008
Authors: Jones, P.J.H. Jew, S. AbuMweis, S.
Publication Name: Metabolism Clinical and Experimental
Publication Details: Volume 57; Pages 1198 – 1203.


Studies have shown that the long chain fatty acid composition of a dietary fat influences whether it will be partitioned for either energy or storage. The objective of this study was to compare the effects of 3 oils differing in fatty acid composition on postprandial energy expenditure and macronutrient oxidation in healthy normal-weight men. Using a randomized crossover design, 15 subjects consumed breakfast meals containing 60 % of energy as fat. The principal source of fat was (a) olive oil rich in oleic acid (18:1n9), (b) sunflower oil rich in linoleic acid (18:2n6), or (c) flaxseed oil rich in linolenic acid (18:3n3). Measurements of resting metabolic rate, thermic effect of food, and postprandial energy expenditure were conducted with indirect calorimetry that recorded O2 consumed and CO2 produced one-half hour before meal consumption and 6 hours after meal consumption. Fat and carbohydrate oxidation rates were calculated from non-protein gaseous exchange. Olive oil feeding showed a significant overall increase in energy expenditure compared with flaxseed oil (P < .0006) and a trend to increased energy expenditure compared with sunflower oil (P < .06). None of the 3 treatments exhibited significant effects on fat or carbohydrate oxidation. In conclusion, diets rich in oleic acid derived from olive oil may offer increased oxidation translating into increased energy expenditure post-prandially. (Authors abstract)
Research suggests that the type of fat consumed influences the partitioning of dietary fat for either energy or storage. The degree of long chain fatty acid unsaturation is proposed to influence the channeling of dietary fat toward either oxidation or storage. Therefore, the quality of fat consumed may become an important aspect to consider in long-term weight management. Some studies have shown a greater oxidation rate of oleic acid compared with linoleic or linolenic acids. Indirect calorimetry techniques can be used to measure energy expenditure as well as net substrate oxidation. Therefore, to better describe how the human body handles different unsaturated fatty acids, a short-term study was conducted to examine whether the degree of unsaturation of an 18-carbon fatty acid chain influences postprandial energy expenditure, fat oxidation, and carbohydrate oxidation in healthy men. Three dietary fatty acids with the same carbon length but with different levels of unsaturation were provided in equal quantities to test human whole-body capacity for oxidation of dietary oleic (18:1n9), linoleic (18:2n6), and linolenic (18:3n3) fatty acids. This is the first study to date that used a single-meal approach and indirect calorimetry to demonstrate that consumption of olive oil rich in oleic acid increases energy expenditure compared with oils containing other long chain unsaturated fatty acids. The results show a preference for oleic acid to enhance energy expenditure. The period of postprandial data collection may have affected the results that are seen in the current study. Another limitation of this type of research is that the quantity and quality of a subject's habitual fat intake can influence substrate oxidation and the partitioning of fat for either energy or storage. The present study used a crossover design, which minimizes potential confounding because every subject serves as his own control. It is proposed by the authors that the differences in the composition of fatty acids in the test oils exert different effects on energy expenditure. In conclusion, the results of this study suggest using indirect calorimetry that human handling of olive, sunflower, and flaxseed oil varies. In particular, the data indicate that olive oil offers a slight advantage toward increased energy expenditure over time in healthy normal weight men. (Editors comments)

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