[Biological effects on premature neonates of a milk formula enriched with alpha-linolenic acid: a multicenter study]

Nervous tissues and the retina are rich in docosahexaenoic acid [DHA, C22: 6(n-3)], an essential fatty acid which is the product of the elongation and desaturation of alpha-linolenic acid [alpha-LnA, C18:3(n-3)]. Lower plasma and membrane DHA levels as well as impaired nervous function (psychomotor development, visual disturbances) have been observed in premature babies receiving standard milk products compared to breast-fed babies and have been related to the lack of long-chain (> C20) fatty acids in these products. In the present study, we have investigated whether it is possible to increase the plasma and erythrocyte DHA level in premature infants by giving them a milk formula enriched in alpha-LnA (1.95% vs 0.55%). Results showed that, after 15 days of feeding, alpha-LnA supplementation significantly increased plasma DHA availability [2.20 vs 1.54% (p < 0.0001) in the plasma phospholipids] and increased DHA level in erythrocyte membranes [3.02 vs 2.54% (n.s.) in the red blood cell phosphatidylethanolamines]. At the LA/alpha-LnA ratio used (6/1), there was only a limited impact on the n-6 pathway which was reflected in a slight decrease in the arachidonic acid (AA) of the plasma phospholipids [6.88 vs 7.53% (p < 0.05) after 15 days]. Furthermore, the AA content of the red blood cell phosphatidylethanolamines was perfectly preserved even after a mean period of 4-5 weeks of feeding [(15.70 vs 14.86% (n.s)]. The observed enhancement in fatty acids of the n-3 series calls for a prospective study investigating whether these improvements are associated with changes in the kinetics of psychomotor development and in the visual function of enriched-formula-fed versus breast-fed babies.