Indicators of long chain polyunsaturated fatty acid status of exclusively breastfed infants at delivery and after 20–22 days

The fatty acid composition of plasma cholesterol esters (CE), erythrocytes (RBC) and mature milk from seven lactating /women and their exclusively breastfed newborns, living on Dominica, were studied. Blood samples were taken from umbilical cord and mother at birth. A sample of breastmilk was collected on day 20-22 postpartum, together with a blood sample from the baby. At birth, cord blood plasma CE and RBC total long chain polyunsaturated fatty acid (LC-PUFA) contents were higher, and linoleic (18:2c,omega6) and alpha-linolenic (18:3c,omega3) acid contents lower, than in corresponding maternal compartments. Cord blood RBC LC-PUFA omega3 content was lower and LC-PUFA omega6 content higher than in maternal RBC. After birth, feeding with human milk led to a drop in LC-PUFA content in the plasma CE fraction, whereas RBC LC-PUFA content remained virtually constant. Current understanding of the origin and relative affinity of fatty acids incorporated in plasma CE and RBC suggests that RBC LC-PUFA content is a more reliable parameter for LC-PUFA status than plasma CE LC-PUFA content. The RBC LC-PUFA data suggest therefore that at birth the newborn has a lower LC-PUFA omega3 status than the mother, and that this does not change during three weeks of exclusive breastfeeding.