Classification of human milks based on their trans 18:1 fatty acid profile and effect of maternal diet

[Background] The diet of breastfeeding women influences the trans fatty acid (TFA) composition of the milk excreted. However, the effects associated to TFA are isomer-dependent and diverse TFA profiles may have different nutritional implications.[Objective] The aim of this research was to evaluate whether certain TFA patterns in human milk fat can be used as indicators of TFA intake from different sources.[Methods] Milk fat from 60 women were examined and classified based on their TFA profile and conjugated linoleic acid (CLA) contents by principal component analysis (PCA).[Results] The PCA of the data allowed the classification of the women into 3 groups depending on milk TFA content and profile. From the 60 subjects, 19 presented a TFA profile characteristic of ruminant products intake, 10 a typical TFA profile of industrial trans fats consumption and 31 a negligible trans content. Superimposed on this, 21 women presented high amounts of docosahexaenoic acid (22:6 n-3) which was related to fish intake.[Conclusions] The present research overcome problems associated to heterogeneous groups in nutritional experiments by a statistical classification of lactating subjects based on the TFA composition of their milk. This classification could be extrapolated to other nutritional studies dealing with TFA analysis and samples of different nature as biological samples or foodstuffs.This work was supported by Agriculture and Agri-Food Canada (Project 223 AAFC-253) and the Spanish Ministry of Education and Science (Project AGL2005-224 04760-C02-01) through a mobility grant to P. Gómez-Cortés.Peer reviewe