Long-chain polyunsaturated fatty acid content in Dutch preterm breast milk; differences in the concentrations of docosahexaenoic acid and arachidonic acid due to length of gestation.

Recognizing the important role of long-chain polyunsaturated fatty acids (LCP) particularly in preterm infant nutrition, we studied the fatty acid composition of breast milk from 65 mothers of very preterm ( < 31 weeks of gestation) and preterm ( > or = 31 and < 36 weeks of gestation) infants. Fatty acids were determined as fatty acid methyl esters by capillary gas chromatography. In accordance with other studies, the increase of capric acid, lauric acid and myristic acid during lactation is influenced by prematurity. Unsaturated fatty acids had the inclination to decrease. Our interest was mainly focused on docosahexaenoic acid (DHA) and arachidonic acid (AA). Accelerated brain growth during the last trimester of gestation requires an extra need for these LCPs. In our study, preterm milk after a gestation period of at least 32 weeks contained the highest amounts of DHA and AA. The Western maternal diet is considered to be low in omega 3 fatty acids, that is why the concentration of DHA in our preterm milk can be regarded as a low amount. As it is the milk of their mothers, and because the amounts are higher than normally found in Western full term breast milk, the contribution of DHA to preterm milk fat (0.34%) might be considered, for the time being, as a safe natural guideline for formulas for preterm infants.

Composition of premature breast-milk during lactation: constant digestible protein content (as in full term milk).

There is much discussion about the protein requirements of (very) preterm infants. The protein content of breast milk plays an important role in this discussion. For this reason, we took a close look at the protein content and its composition in premature breast milk. Complete 24 h expressions-were examined using the Kjedahl method, GPC, SDS-PAGGE and nephelometric detection of sIgA. Colostrum of premature breast milk contains a large amount of undigestible proteins, up to 70% of true protein, which decreases to 20-40% in transitory and mature preterm milk. The NPN fraction of mature preterm breast milk was, dependent on the degree of prematurity 20-25%; increasing during lactation from about 18% to 22-26%. This means that, depending on the lactation period only 30-60% of the total protein content of breast milk is available for body protein synthesis. In absolute amounts, digestible protein is reasonably stable during lactation.