Patric Fontannaz

Temporal Changes of Human Breast Milk Lipids of Chinese Mothers

Fatty acids (FA), phospholipids (PL), and gangliosides (GD) play a central role in infant growth, immune and inflammatory responses. The aim of this study was to determine FA, PL, and GD compositional changes in human milk (HM) during lactation in a large group of Chinese lactating mothers (540 volunteers) residing in Beijing, Guangzhou, and Suzhou. HM samples were collected after full expression from one breast and while the baby was fed on the other breast. FA were assessed by direct methylation followed by gas chromatography (GC) analysis. PL and GD were extracted using chloroform and methanol. A methodology employing liquid chromatography coupled with an evaporative light scattering detector (ELSD) and with time of flight (TOF) mass spectrometry was used to quantify PL and GD classes in HM, respectively. Saturated FA (SFA), mono-unsaturated FA (MUFA), and PL content decreased during lactation, while polyunsaturated FA (PUFA) and GD content increased. Among different cities, over the lactation time, HM from Beijing showed the highest SFA content, HM from Guangzhou the highest MUFA content and HM from Suzhou the highest n-3PUFA content. The highest total PL and GD contents were observed in HM from Suzhou. In order to investigate the influence of the diet on maternal milk composition, a careful analyses of dietary habits of these population needs to be performed in the future.

Quantification of glycerophospholipids and sphingomyelin in human milk and infant formula by high performance liquid chromatography coupled with mass spectrometer detector

Phospholipids and sphingomyelin have a central role in infant nutrition, phospholipid acting as a nutrient carrier of long chain polyunsaturated fatty acids and sphingomyelin having an important role in cognitive function. However, analytical methods to precisely characterize and quantify these compounds in maternal milk are needed. Phospholipids and sphingomyelin were extracted using chloroform and methanol and separated on Polaris 3 Si column 250×2.0mm from Varian and analyzed by high performance liquid chromatography (HPLC) coupled with mass spectrometer detector (MS). The analytical method was validated and repeatability, intermediate reproducibility, and recovery values were calculated. The relative standard deviation of repeatability (CV(r)) and intermediate reproducibility (CV(iR)) values ranged between 2.3 and 7.2% and 9.5 and 17.8%, respectively and the recovery values between 96 and 109%. Finally, the validated method was tested on human milk samples and on infant formula which were analysed also by HPLC coupled with evaporative light scattering detector (ELSD). In human milk, sphingomyelin (9.28mg100mL-1) was the most abundant compound, followed by phosphatidylcholine (5.39mg100mL-1), phosphatidylethanolamine (2.85mg100mL-1) and phosphatidylinositol (1.82mg100mL-1).