It was investigated whether concentrations of DHA and AA would increase if preterm infants were fed formula containing 0.4% DHA and AA instead of 0.2% DHA and AA, and whether these concentrations would be more similar to those of preterm infants fed human milk.

Infants (bw <1500 g and/or ga <32 w) received preterm formula or fortified human milk until term. Thereafter, they were randomized to a postdischarge formula (n = 30, PDF) or a standard term formula (n = 31, TF) until 6 months CA. Twelve infants were fed human milk exclusively until 3 months CA (HM3). At term, 3 and 6 months CA a venous blood sample was drawn and LC-PUFA status in the red blood cell was determined by capillary gas chromatography/flame ionisation detection.

AA, DHA and the DHA/AA ratio were higher in infants fed PDF than in infants fed TF at 3 and 6 months CA. AA was higher in HM3 infants than in PDF/TF infants at 3+6 months CA. DHA was lower in HM3 infants than in PDF infants at all times.

Feeding preterm infants formula containing higher levels of DHA and AA (ratio1:1) after term CA increases both the DHA and AA concentration and the DHA/AA ratio. Preterm infants fed human milk after term CA have lower DHA status than infants fed enriched formula. This might be due to the Western style diet of their mothers.