Determination of the optimal ratio of linoleic acid to alpha-linolenic acid in infant formulas.
The fatty acid composition of erythrocyte total lipids taken from a group of term infants 10 weeks after being fed a commercial infant formula with a high ratio of linoleic acid (18:2n-6) (LA) to alpha-linolenic acid (18:3n-3) (ALA) (19:1; LA, 14%; ALA, 0.7%; group A, n = 10) was compared with the fatty acid composition of erythrocytes from infants fed formulas that contained LA/ALA ratios reduced by either increasing ALA (4:1; LA, 13%; ALA, 3.3%; group B, n = 11) or decreasing LA (3:1; LA, 3.5%; ALA, 1.1%; group C, n = 8). Results were compared with those in an age-controlled group (n = 9) of breast-fed infants. Decreasing the LA/ALA ratio increased n-3 C20 and C22 fatty acid incorporation (formula B = 8.98% +/- 0.65%; formula C = 9.30% +/- 0.95%) relative to formula A (5.97% +/- 0.76%; p less than 0.05). Although docosahexaenoic acid (22:6n-3) (DHA) incorporation was highest in infants fed formulas B and C (4.78% +/- 0.45% and 4.48% +/- 0.49%, respectively) relative to formula A (3.47% +/- 0.46%; p less than 0.05), it did not reach levels found in breast-fed infants (6.55% +/- 1.23%; p less than 0.05). In addition, levels of arachidonic acid (20:4n-6) (AA) were lower in all formula-fed groups (p less than 0.05) relative to those in breast-fed infants. Based on some equations, it is predicted that AA levels in tissues of infants fed lower LA/ALA ratios would be reduced even further. Because both AA and DHA are probably essential for normal neural development of the infant, formulas with LA/ALA ratios below 4:1 are likely to result in fatty acid profiles notably different from those of breast-fed infants.
Department of Paediatrics and Child Health, Flinders Medical Centre, Adelaide, South Australia.
K J
KJ
Clark
M
M
Makrides
M A
MA
Neumann
R A
RA
Gibson
D016718:Arachidonic Acid / Q000097:blood; D001942:Breast Feeding; D004281:Docosahexaenoic Acids / Q000097:blood; D005227:Fatty Acids / Q000032:analysis / Q000097:blood*; D006801:Humans; D007225:Infant Food / Q000032:analysis; D007231:Infant, Newborn / Q000097:blood*; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000032:analysis; D008042:Linolenic Acids / Q000032:analysis; D017962:alpha-Linolenic Acid
D005227:Fatty Acids; D008041:Linoleic Acids; D008042:Linolenic Acids; D017962:alpha-Linolenic Acid; D004281:Docosahexaenoic Acids; D016718:Arachidonic Acid; D019787:Linoleic Acid