Similar distribution oftransfatty acid isomers in partially hydrogenated vegetable oils and adipose tissue of Canadians

Abstract

The objective of this study was to evaluate the composition of trans fatty acids in the subcutaneous fat of Canadians relative to the composition of dietary sources of trans fatty acids. The fatty acid composition, total trans fatty acid content, and the geometric and positional isomer distribution of unsaturated fatty acids of subcutaneous adipose tissue of Canadians were determined using a combination of capillary gas–liquid chromatography and silver nitrate thin-layer chromatography. The mean total trans fatty acid content was 6.80% at the abdominal site and 5.80% at the lateral thigh site. Total trans isomers of linoleic acid (18:2n−6) were present at 1.17% in abdominal and 1.59% in thigh adipose tissue, with 9c,12t-18:2 being the most prevalent isomer followed by 9c-13t-18:2 and 9t,12c,-18:2. The oleic acid (18:1) trans isomer distribution in adipose tissue differed from that in butter fat, but it was similar to that in partially hydrogenated vegetable oils. The reverse was true for the 18:1 cis isomers. Total 18:1 trans isomers were inversely related to 18:2n−6 content in adipose tissue, suggesting the trans fatty acid intake is inversely related to the intake of linoleic acid. Partially hydrogenated vegetable oils appear to be the major source of trans fatty acids in adipose tissue of Canadians.Key words: trans fatty acids, adipose tissue, partially hydrogenated vegetable oil, linoleic acid.