Docosahexaenoic and arachidonic acid content of serum and red blood cell membrane phospholipids of preterm infants fed breast milk, standard formula or formula supplemented with n-3 and n-6 long-chain polyunsaturated fatty acids

The contents of docosahexaenoic (DHA) and arachidonic acid (AA) of plasma and red blood cell membrane phospholipids were studied in 41 very low birth weight infants fed either breast milk (n = 18), a standard formula without long-chain polyunsaturated fatty acids with 20 or 22 carbon atoms (LCP) but with alpha-linolenic acid and linoleic acid (n = 11) or a formula additionally supplemented with n-3 and n-6 LCP in relations typical for human milk (n = 12) after 2, 6, and 10 weeks of feeding. The content of DHA and AA in plasma phospholipids declined in the infants fed the LCP-free formula but remained more or less constant during the whole feeding period in those infants fed breast milk as well as in those fed the LCP-supplemented formula. The differences between the group fed the LCP-free standard formula and the two groups fed LCP-containing diets became significant during the first 2 weeks of feeding. In contrast, there were no differences between the group fed breast milk and the group fed the supplemented formula during the study period. Similar effects could be observed regarding the composition of red blood cell membrane phospholipids, but the differences between the infants fed the LCP-free standard formula and the two other groups with LCP-containing diets were significant only for AA. The data indicate that very low birth weight infants are unable to synthesize LCP from a-linolenic acid and linoleic acid in sufficient amounts to prevent a decline of LCP in plasma and red blood cell phospholipids. Additionally, the data show, that supplementation of formulas with n-3 and n-6 LCP in amounts typical for human milk fat results in similar fatty acid profiles of plasma and red blood cell membrane phospholipids as found during breast milk feeding. Conclusion Supplementation of formula with long-chain polyunsaturated fatty acids improves the LCP status of very low birth weight infants.