Stability of n-3 fatty acids in human fat tissue aspirates during storage

The content of n-3 (omega 3) polyunsaturated fatty acids in fat tissue is an indicator of their long-term consumption. Therefore, a method for determining n-3 fatty acids in human fat tissue microbiopsies was validated and the stability of n-3 fatty acids in biopsies was checked under various conditions of storage. Methyl esters were prepared from 25 to 35 mg adipose tissue and separated by capillary gas chromatography. Recovery of added eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) was 98-105%. The change after storage of fat samples at room temperature or at 4, -20, or -80 degrees C for 3 mo averaged +3.3% for EPA and +2.1% for DHA, with no effect of temperature. Storage at +20 or -80 degrees C for 7 mo yielded no perceptible change in EPA, DHA, or five other n-3 polyunsaturated fatty acids. EPA and DHA concentrations in adipose tissue aspirates are remarkably stable and deserve attention as biomarkers in epidemiological studies.