Lactational changes of fatty acids and fat-soluble antioxidants in human milk from healthy Chinese mothers.

This study aimed to quantify the composition of fatty acids, tocopherols and carotenoids in human milk, with special emphasis on the lactational changes. Colostrum, transitional, and mature milk samples were collected longitudinally from the same 42 healthy, well-nourished Chinese mothers. Fatty acids were quantified by gas chromatography with carotenoids (carotenes and xanthophylls) and tocopherols (α-, γ-tocopherol) determined by high-performance liquid chromatography. Total fatty acids content increased from 15.09 g/L in colostrum to 32.57 g/L in mature milk with the percentages of DHA and ARA decreased. The ratio of n-6/n-3 PUFA and ARA/DHA remained constant during lactation at around 11:1 and 1.3:1, respectively. Both α-tocopherol and γ-tocopherol decreased over lactation with the ratio of α-/γ-tocopherol declined significantly from 7.21:1 to 4.21:1 (P < 0.001). Carotenoids all dropped from colostrum to mature milk as the less polar carotenes dropped by 88.67% while xanthophylls only dropped by 35.92%. Lutein predominated in both transitional and mature milk carotenoids (51.64~52.49%), while colostrum carotenoids were mainly composed of lycopene (32.83%) and β-carotene (30.78%). The concentrations of tocopherols and xanthophylls but not carotenes were positively associated with milk total fatty acids content. These results suggested that colostrum and mature milk contained divergent lipid profiles and selective transfer mechanisms related with polarity might be...
Source: The British Journal of Nutrition - Category: Nutrition Authors: Tags: Br J Nutr Source Type: research