Journal Name:
Metabolism
Article Title:
The effect of dietary oleic, linoleic, and linolenic acids on fat oxidation and energy expenditure in healthy men
Date Written:
2008
Volume:
57
Number:
9
Page:
1198
Author(s):
Jones, P.J.; Jew, S.; AbuMweis, S.
Article:
Research is suggesting that the type of fat consumed influences the partitioning of dietary fat for either energy or storage. In particular, the degree of long chain fatty acid unsaturation is proposed to influence the channeling of dietary fat toward either immediate oxidation or storage. Therefore, the quality of fat consumed may become an important aspect to consider in long-term weight management. Studies have revealed a pattern of selective oxidation of long chain unsaturated fatty acids over long chain saturated fatty acids. However, differences between the various unsaturated fatty acids are less clear. Some studies have shown a greater oxidation rate of oleic acid compared with linoleic or linolenic acids. Research also have shown that the long chain fatty acid composition of a dietary fat influences whether it will be partitioned for either energy or storage.
To better describe how the human body handles different unsaturated fatty acids, this 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 (18:1n-9), linoleic (18:2n-6), and linolenic (18:3n-3) fatty acids.
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 (18:1n-9), (b) sunflower oil rich in linoleic acid (18:2n-6), or (c) flaxseed oil rich in linolenic acid (18:3n-3). Measurements of resting metabolic rate, thermic effect of food, and postprandial energy expenditure were conducted with indirect calorimetry that recorded O(2) consumed and CO(2) produced one-half hour before meal consumption and 6 hours after meal consumption. Fat and carbohydrate oxidation rates were calculated from nonprotein gaseous exchange.
This is the first study using 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. None of the 3 treatments exhibited significant effects on fat or carbohydrate oxidation. A plausible biological mechanism to explain the preferential oxidation of oleic acid is that it is preferentially incorporated into TG, which are a ready source of energy. Rats fed a diet rich in olive oil compared with one rich in sunflower oil experienced an up-regulation of uncoupling protein, a protein that allows heat production by uncoupling respiration from adenosine triphosphate synthesis, which is an important component of energy expenditure.
It is proposed 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 for the first time 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. In conclusion, diets rich in oleic acid derived from olive oil may offer increased oxidation translating into increased energy expenditure postprandially.
Back to New research paper