Abstract
Background/objectives: This study aimed to characterize the fatty acid (FA) profile of breast milk (BM) at 7 days (T7) and 1 month postpartum (T30) using gas chromatography-mass spectrometry (GC-MS) and to evaluate associations between maternal diet during pregnancy and BM FA composition. Methods: A prospective observational cohort study was conducted from March 2022 to October 2023, involving mothers grouped by gestational age at delivery (32 weeks, 32-36.6 weeks, and >37 weeks). Results: BM lipid profiles were generally similar across gestational groups, with notable differences at T7 in saturated fatty acids (SFAs), myristic acid, monounsaturated fatty acids (MUFAs), erucic acid, nervonic acid, and some FA ratios. At T30, differences persisted in SFAs, MUFAs, myristic acid, and MUFA/SFA. At T7, red meat intake was positively correlated with stearic acid; white meat intake was negatively associated with multiple FAs (including ω-3) but positively with linoleic. Cheese correlated positively with caprylic acid; milk negatively with pentadecylic acid; and dried fruit positively with MUFA. At T30, fish consumption was prevalently positively related to DHA, EPA, and Omega-3, while red meat was positively associated with arachidic acid and margaric acid and negatively with di-homo-gamma linolenic acid. White meat showed a predominantly negative correlation with DHA, EPA and MUFA. Milk intake showed both positive (i.e., caproic acid) and multiple negative FA associations. Cheese was positively associated with caprylic acid, while dried fruit intake was positively linked to oleic acid and MUFA. Conclusions: Despite stable total lipid content, gestational age influenced specific FA profiles. These shifts may reflect adaptive responses to neonatal metabolic and neurodevelopmental needs. Understanding such mechanisms could guide tailored nutritional strategies, especially for preterm infants.