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United States Department of Agriculture

Agricultural Research Service

Title: A Physiologic Compartmental Analysis of Alpha-Linolenic Acid Metabolism in Adult Humans

Authors
item Pawlosky, Robert
item Novotny, Janet
item Hibbeln, Joseph - NIH
item Salem, Jr, Norman - NIH

Submitted to: Journal of Lipid Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 5, 2001
Publication Date: December 1, 2001
Citation: Pawlosky, R.J., Novotny Dura, J., Hibbeln, J., Salem, Jr, N. 2001. A physiologic compartmental analysis of alpha-linolenic acid metabolism in adult humans. Journal of Lipid Research. 42(8):1257-1265

Interpretive Summary: The American Heart Association has recommended increasing the dietary intake of the long-chain omega-3 fatty acids, docosahexaenoic acid (22:6n-3) and eicosapentaenoic acid (20:5n-3) because of their well established benefits to cardiovascular health. These fatty acids are found in fish and seafoods, which do not make up a regular part of a "typical" American diet. For the majority of Americans, the biosynthesis of long-chain n-3 polyunsaturated fatty acids from linolenic, 18:3n-3, is a major contributor to the body's supply of 20:5n-3 and 22:6n-3. An accurate model of linolenic acid metabolism in humans based on direct data obtained from an isotope tracer is needed. A compartmental model was derived from the plasma concentration-time curves for d5-18:3n-3, d5-20:5n-3, d5-22:5n-3, and d5-22:6n-3 in eight healthy subjects. The model predicted that only about 0.2% of the plasma 18:3n-3 was destined for synthesis of 20:5n-3. The inefficiency of the conversion of 18:3n-3 to 20:5n-3 indicates that the biosynthesis of long-chain n-3 PUFAs from linolenic acid is very limited in healthy subjects and in order to obtain these fatty acids, Americans should increase their intake of fish and seafoods.

Technical Abstract: The American Heart Association has recommended increasing the dietary intake of the long-chain omega-3 fatty acids, docosahexaenoic acid (22:6n-3) and eicosapentaenoic acid (20:5n-3) because of their well established benefits to cardiovascular health. These fatty acids are found in fish and seafoods, which do not make up a regular part of a "typical" American diet. For the majority of Americans, the biosynthesis of long-chain n-3 polyunsaturated fatty acids from linolenic, 18:3n-3, is a major contributor to the body's supply of 20:5n-3 and 22:6n-3. An accurate model of linolenic acid metabolism in humans based on direct data obtained from an isotope tracer is needed. A compartmental model was derived from the plasma concentration-time curves for d5-18:3n-3, d5-20:5n-3, d5-22:5n-3, and d5-22:6n-3 in eight healthy subjects. The model predicted that only about 0.2% of the plasma 18:3n-3 was destined for synthesis of 20:5n-3. The inefficiency of the conversion of 18:3n-3 to 20:5n-3 indicates that the biosynthesis of long-chain n-3 PUFAs from linolenic acid is very limited in healthy subjects and in order to obtain these fatty acids, Americans should increase their intake of fish and seafoods.

Last Modified: 11/26/2014
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