Fatty acid composition in breast milk and serum phospholipids of healthy term Chinese infants during first 6 weeks of life

AIM: To compare the fatty acid (FA) pattern in early and mature breast milk with that in plasma phospholipids of cord blood and breast-fed infants. METHODS: Forty-five mother-infant pairs from western Shanghai were studied. All infants, born at term with normal weight and length, were examined at birth and days 5 and 42. FA was analyzed by capillary gas-liquid chromatography. RESULTS: Cord blood showed higher concentration of long-chain polyunsaturated FA (LCPUFA) but lower saturated (SFA) and monounsaturated (MUFA) FA than postnatal infants' plasma. SFA decreased with age in the infants, but MUFA and linoleic acid (LA, 18:2omega6) increased. LCPUFA were lower in the plasma of 5-day-old infants than in cord blood, but LA was 80%, alpha-linolenic acid (ALA, 18:3omega3) 33% and the ratio omega-6/omega-3 42% higher. At day 42, LA increased further, LCPUFA remained similar, and was in breast milk lower than at day 5, while ALA and gamma-linolenic acid (18:3omega6) were higher. The activity index of desaturases indicated high Delta9 activity in breast milk and high activity of Delta5 desaturase in the infants. CONCLUSION: Breast milk FA composition changed markedly from day 5 to 42 with increasing correlation to infants' plasma. Calculation of desaturase activities suggested high capacity of LCPUFA synthesis.