Trans Fatty Acids in Plasma, Serum, and Red Blood Cells

Abstract

Trans‐fatty acids (TFA) intake was associated with increased risk of cardiovascular disease. However, little is known about TFA concentrations in human blood. Studies suggested that individuals with the same fatty acid (FA) intake may have different concentrations of regular FA in red blood cells (RBC), plasma, and serum due to a number of factors including genetics and lifestyle. This created the need to assess TFA concentrations in different blood specimens from people to obtain information about TFA exposure and metabolism. We investigated the TFA distribution in RBC, plasma, and serum using convenience samples from 66 adults. Samples were analyzed using an isotope dilution‐gas chromatography‐mass spectrometry method validated for the analysis of 28 FA, including the 4 major TFA: palmitelaidic acid, elaidic acid, vaccenic acid, and linoelaidic acid. The TFAs were detected in all samples, with median total TFA concentrations of 21.12 μM in RBC, 17.86 μM in plasma, and 20.88 μM in serum. The median percent of total TFA was similar for elaidic and vaccenic acids in all three matrices. The median percent of total TFA was 1/3 lower in the RBC than in the plasma and serum for palmitelaidic acid and half as high for linoelaidic acid in RBC as in plasma and serum. The differences in TFA distributions suggest differences in metabolism of individual TFA.