Variability in Human Fatty Acids Profiles Based on Blood Fractions and Metabolic Conditions

Fatty acids play a crucial role in various metabolic pathways, with their proportions and distributions across different cells and tissues influenced by diet and metabolism. In addition to providing energy through oxidative reactions, fatty acids serve as substrates for the synthesis of numerous molecules involved in cellular signaling processes. Therefore, quantifying fatty acids in biological samples is essential for ensuring the quality of clinical trials involving lipids and for understanding the relationship between fats and health conditions. However, the fatty acid profiles reported in clinical trials can exhibit significant heterogeneity due to both endogenous and exogenous factors, including the metabolic condition of the patients and the specific blood fraction analyzed. This variability makes difficult the comparison of results across studies. Moreover, despite the crucial role of fatty acids in immune response, most results are derived from erythrocytes, plasma, or serum, providing limited information on their variability in leukocytes. Thus, the hypothesis of this study is that metabolic conditions, characterized by fasting or postprandial states, can influence the fatty acid profile depending on the blood fraction analyzed. To evaluate this hypothesis, six healthy individuals will be supplemented with fish oil for eight weeks, with blood samples collected before and after the intervention. Fatty acid levels will be measured using gas chromatography coupled with mass spectrometry in total plasma, phospholipids, erythrocytes, and leukocytes. The results will help estimate the variability caused by metabolic states according to the blood fraction, which is critical when conducting clinical trials in patients where fasting cannot be assured and is essential for comparing fatty acid profiles in studies involving leukocytes.