Abstract
OBJECTIVES: The study aimed to investigate the levels of RRR-α-tocopherol and carotenoids in maternal blood, cord blood and breast milk samples of different lactation stages from healthy Chinese mothers and to explore their associations with social demographical characteristics. METHODS: The study was part of a MUAI study (Maternal Nutrition and Infant Investigation, ChiCTR1800015387). SAMPLES COLLECTION: Healthy lactating mothers (aged 20–35 year) with single, full-term delivery were recruited in Tianjin city. Maternal blood, cord blood, colostrum, transitional milk and mature milk samples were collected. SAMPLE ANALYSIS: The levels of tocopherols and carotenoids (lutein, zeaxanthin, β-cryptoxanthin, β-carotene,lycopene) were determined by HPLC. The compositions of α-tocopherol stereoisomers were determined by chiral HPLC. RESULTS: Maternal blood plasma contained higher α-tocopherol level than cord blood plasma and breast milk samples. In breast milk samples, the levels of α-tocopherol reduced with lactation stages for about three times. Even though the levels of α-tocopherol varied in plasma and breast milk, RRR-α-tocopherol (RRR) were predominant in all samples, accounting for 83%∼90% of α-tocopherol. The results suggestted RRR was preferred stereoisomers for maternal and newborn. Carotenoids were also more abundant in maternal blood plasma than in cord blood plasma and breast milk samples. The total carotenoids level in maternal blood plasma was about 8 times higher than cord blood plasma and 2.5 times of colostrum. The level of total carotenoids decreased with the lactation stages due to the dramatically dropped of lycopene and β-carotene. In contrast, lutein level remained stable in breast milk and was the most abundant carotenoids in transitional milk, mature milk and blood plasma, suggesting that fetus and infant had continuous demand for lutein. The levels of carotenoids and RRR in maternal and cord blood plasma were related to parity, pre-pregnancy and prenatal BMI. The levels of carotenoids and RRR in breast milk samples were correlated with cord plasma. CONCLUSIONS: RRR- α-tocopherol and lutein were the most abundant α-tocopherol and carotenoids in Chinese cord blood plasma and breast milk, suggesting that they may play more important roles in early life. FUNDING SOURCES: This study was funded by Abbott Nutrition R&D Centre, Shanghai, China.