Tandem mass spectrometric analysis of human milk triacylglycerols from normal weight and overweight mothers on different diets

The composition and structures of TAGs in the human milk from mothers with different food choices and prepregnancy body mass index were determined with two tandem mass spectrometric methods (negative APCI–MS/MS and positive UHPLC/ESI–MS/MS) at the infant’s age of three months. The normal weight mothers with recommended food choices had more 18:3n-3 and less 18:0 in their milk than normal weight mothers with non-recommended food choices. A significant difference between the normal weight mothers on the non-recommended food choices and the other groups was seen in acyl carbon number: number of double bond (ACN:DB)-groups 54:6, 54:5, 54:3 and 54:2. In ACN:DB 52:7 and 52:6 the two recommended food choices–groups differed significantly from the two non-recommended food choices–groups. The regioisomerism of TAGs varied little despite differences in mother’s weight and diet with sn-18:1-16:0-18:1 as the most prevalent regioisomer in the milk (13.8 ± 2.7%). The results of this study highlight the importance of structure specific human milk substitutes and the careful selection of the MS/MS methods for analysis of mixtures of several isobaric TAGs.