Lipids

, Volume 36, Issue 3, pp 315–317

Changes in conjugated linolenic acid composition within samples obtained from a single source

Authors

    • Oil Chemical ResearchNational Center for Agricultural Utilization Research, USDA, ARS
  • L. C. Copes
    • Oil Chemical ResearchNational Center for Agricultural Utilization Research, USDA, ARS
  • E. L. Walter
    • Oil Chemical ResearchNational Center for Agricultural Utilization Research, USDA, ARS
Communication

DOI: 10.1007/s11745-001-0723-7

Cite this article as:
Adlof, R.O., Copes, L.C. & Walter, E.L. Lipids (2001) 36: 315. doi:10.1007/s11745-001-0723-7

Abstract

Conjugated linoleic acid (CLA; 9c, 11t-18∶2) and CLA isomers have been reported, in animals, to exhibit a variety of health-related benefits. Silver ion high-performance liquid chromatography (Ag-HPLC) was found to provide better resolution of the isomes than gas chromatography. Most commercially available samples of CLA, prepared by base-catalyzed isomerization of linoleic acid (9c, 12c-18∶2), are conposed of mixtures of four major isomers. While these isomers have been characterized, we found significant changes in CLA isomer ratios within samples obtained from the same producer/commercial supplier over a period of 1.5 yr. In the first sample, the four cis/trans isomers (8t, 10c-18∶2, 9c, 11t-18∶2, 10t, 12c-18∶2 and 11c, 13t-18∶2) were present in a ratio of approximately 1∶2∶2∶1, while in the second sample they were present in almost equal proportions. If indeed certain daily levels of CLA intake are required to produce suggested health benefits in humans, changes in concentrations of specific CLA isomers could significantly impact these effects. Care must be taken to analyze the CLA used in human and animal studies.

Key Words

ConjugatedlinoleicCLAcompositionisomersHPLCGC

Abbreviations

Ag-HPLC

silver ion high-performance liquid chromatography

CLA

conjugated linoleic acid

GC

gas-liquid chromatography

Copyright information

© AOCS Press 2001