Total lipid content and fatty acid composition of preterm human milk.

The total lipid content and fatty acid composition of preterm human colostrum and milk were analyzed from aliquots of 24-h collections of colostrum, transitional milk, and mature milk obtained from 21 women who had delivered premature infants with a mean birth weight of 1,049 +/- 38 g (mean +/- SEM) and a mean gestational age of 29 +/- 0.4 weeks. The total lipid content increased significantly with time of lactation (p less than 0.001), from 1.99 +/- 0.25 g/dl in colostrum to 3.89 +/- 0.28 g/dl in mature milk. With respect to the fatty acid pattern, the percentages of 12:0 and 14:0 increased significantly (p less than 0.001), while those of 16:0 (p less than 0.05) and 18:1 (p less than 0.001) decreased significantly with time of lactation. The percentages of 10:0, 16:1, 18:0, 18:2, and 18:3 did not vary significantly with the duration of lactation. Similar compositional changes have been described in term human colostrum and milk as the duration of lactation progresses.