RESUMO
The evaluation of the benefits of omega-3 fatty acid supplementation in humans requires the identification and characterization of suitable biomarkers of its incorporation in the body. The reference method for the evaluation of omega-3, gas chromatography, is difficult to apply in clinical practice because of its low throughput and does not provide information about the incorporation of specific fatty acids in lipid species and the potential effects of supplementation on lipid classes. We used a quantitative lipidomic approach to follow the incorporation of omega-3 fatty acids into plasma lipids in cystic fibrosis patients (n=50) from a randomized controlled clinical trial after the supplementation of seaweed oil enriched with docosahexaenoic acid (DHA). Lipidomic analysis accurately showed the distribution of fatty acids in different lipid classes after omega-3 supplementation, and the performance in determining the compliance to supplementation was similar to that of gas chromatography coupled to mass spectrometry. Twelve months after fatty acid supplementation, DHA was predominantly incorporated into highly unsaturated cholesteryl esters (110.9±16.2 vs. 278.6±32.6 µM, mean±S.E.M.) and phosphatidylcholine (142.4±11.9 vs. 272.9±21.4 µM) and, to a lesser extent, into phosphatidylethanolamine (9.4±0.8 vs. 15.5±1.5 µM) and triglycerides (0.4±0.04 vs. 1.1±0.12 µM). In addition, a technique was developed for the fast measurement of the DHA/arachidonic acid ratio to simplify the follow-up of nutritional intervention with DHA-enriched foods. We conclude that lipidomics is a suitable approach for monitoring the incorporation of omega-3 fatty acids in nutritional studies.