Blood lipid docosahexaenoic and arachidonic acid in term gestation infants fed formulas with high docosahexaenoic acid,low eicosapentaenoic acid fish oil

The effect of fish oil high in docosahexaenoic acid (22∶6n−3) and low in eicosapentaenoic acid (20∶5n−3) in formula on blood lipids and growth of full-term infants was studied. Infants were fed formula with about 15% oleic acid (18∶1), 32% linoleic acid (18∶2n−6), 4.9% linolenic acid (18∶3n−3) and 0, 0.10 or 0.22% 22∶6n−3, or 35% 18∶1, 20% 18∶2n−6, 2.1% 18∶3n−3 and 0, 0.11 or 0.24% 22∶6n−3 from 3 d to 16 wk of age (n=16, 18, 17, 21, 17, 16, respectively). The formulae had <0.1% 20∶5n−3 and no arachidonic acid (20∶4n−6). Breast-fed infants (n=26) were also studied. Plasma phospholipid and red blood cell (RBC) phosphatidylcholine (PC) and phosphatidylethanolamine (PE) fatty acids were determined at 3 d and 4, 8, and 16 wk of age. These longitudinal analyses showed differences in blood lipid 22∶6n−3 between breast-fed and formula-fed infants depending on the feeding duration. At 16 wk, infants fed formula with 0.10, 0.11% 22∶6n−3, or 0.22% 22∶6n−3 had similar 22∶6n−3 levels in the plasma phospholipid and RBC PC and PE compared with breast-fed infants and higher 22∶6n−3 than infants fed formula without 22∶6n−3. Formula with 0.24% 22∶6n−3, however, resulted in higher plasma phospholipid 22∶6n−3 than in breast-fed infants at 16, but not 4 or 8 wk of age. Plasma and RBC phospholipid 20∶4n−6 was lower in formula-fed than breast-fed infants, but no differences in growth were found. Higher blood lipid C₂₀ and C₂₂ n−6 and n−3 fatty acids in infants fed formula with 20% 18∶2n−6 and 2.4% 18∶3n−3 compared with 32% 18∶2n−6 and 4.9% 18∶3n−3 show the increase in blood lipid 22∶6n−3 in response to dietary 22∶6n−3 depending on other fatty acids in the formula.