Introduction: The structure of trans unsaturated fatty acids (TFAs) includes at least one double bond with a trans configuration. Numerous studies have shown that TFAs influence negative changes in blood lipid profile, may initiate or accelerate the course of many inflammatory diseases, and reduce n-6 and n-3 fatty acids' utilization. Their presence in tissues and systemic fluids is mainly the result of ingestion of TFA-containing foods. The objective of this study was to determine the concentration profiles of elaidic and vaccenic acids in human milk, and the existence of potential correlations between the levels of trans-unsaturated fatty acids and long chain polyunsaturated fatty acids.
Materials and methods: The study group consisted of 53 lactating women, aged 18-39 years, 5-6 weeks after delivery. Elaidic and vaccenic acid levels were determined in human milk. Fatty acid methyl esters were injected onto the capillary column of an Agilent 6890M gas chromatography system integrated with an autosampler. Geometrical and positional isomers of fatty acids were identified by comparing their retention times with those of the fatty acid standards from Sigma-Aldrich. The content of individual fatty acids was determined from the reference curves and expressed in mg/mL.
Results: The level of elaidic acid was 0.2572 ± 0.1811 mg/mL, and the level of vaccenic acid was 0.2736 ± 0.1852 mg/mL. No negative correlations between the levels of the analyzed TFAs and PUFAs were observed in human milk.
Conclusions: The levels of elaidic and vaccenic acid were similar and had no negative influence on the levels of arachidonic acid and docosahexaenoic acid.