Medium- and long-chain triacylglycerols composition in preterm and full-term human milk across different lactation stages

Human milk is a natural source of medium-chain fatty acids (MCFAs). It is generally acknowledged that MCFAs exist in medium-chain triacylglycerols (MCTs). However, a previous study revealed that human milk is naturally rich in medium- and long-chain triacylglycerols (MLCTs). Few data are available on the MLCT composition of preterm milk. This study compared the MCFA and MLCT profiles in human milk from mothers after preterm (28–37 weeks) and term (>37 weeks) delivery during three lactational stages. The results showed that almost half of the triacylglycerol species in human milk are MLCT, accounting for approximately 30% of the total TAGs, mainly composed of one MCFA and two long-chain fatty acids, that is, MLL-type MLCT. In addition, MCFAs and MLCTs showed an increase from colostrum to transitional milk, while they were comparable between preterm and full-term milk. This research could help to develop infant formula, which is of great significance for infants. [Display omitted] •MLCT is the main existence form of MCFAs in human milk.•MLCTs are an important TAG structure with the MLL-type abundant in human milk.•Almost half of TAG molecules in human milk are MLCTs, accounting for around 30% of total TAGs.•Lactation was a major factor influencing MCFAs and MLCTs profile in human milk.•Gestation had little impact on MCFAs and MLCTs profile in human milk.