Azab SM, de Souza RJ, Teo KK, et al. - Using a high throughput method (< 4 min/sample) based on multisegment injection-non-aqueous-capillary electrophoresis–mass spectrometry (MSI-NACE-MS), experts aspired to explore if specific serum non-esterified fatty acid (NEFAs) have utility as biomarkers of dietary fat intake in women. Among pregnant women with contrasting dietary patterns (n = 50), circulating NEFAs associated with long-term/habitual food intake were first identified. In addition, acute changes in serum NEFA trajectories were analyzed in non-pregnant women (n = 18) following high-dose (5 g/day) fish oil supplementation or isoenergetic sunflower oil placebo over 56 days. In the cross-sectional study, serum omega-3 (ω-3) FA associated with self-reported total ω-3 daily intake, notably eicosapentaenoic acid (EPA) as its NEFA, while pentadecanoic acid was linked to full-fat dairy intake, outcomes consistent with outcomes from total FA serum hydrolysates. According to findings, MSI-NACE-MS provides a rapid method for the quantification of serum NEFAs and objective monitoring of dietary fat intake in women complementing diet records or questionnaires on food frequency.