Effects of dietary long-chain polyunsaturated fatty acids on the essential fatty acid status of premature infants.

The effect of different diets on the percentage content of long-chain polyunsaturated fatty acids (LCP; metabolites of linoleic and alpha-linolenic acids) in plasma lipids was studied in 29 premature infants on days 4 and 21 of life. Eleven infants were fed human milk which supplies LCP (1.7% of the fatty acids), 10 a commercially available milk formula without LCP, and 8 a new formula enriched with LCP of the omega-6 and the omega-3 series (0.5% LCP). LCP values in plasma lipids remained stable during the observation period in infants fed human milk. In contrast, LCP decreased markedly in plasma lipids of infants fed the conventional formula. Since the precursor fatty acids linoleic and alpha-linolenic acids were high in their diet and plasma, this finding indicates that premature infants have a limited capacity for LCP biosynthesis and may require their dietary supplementation. Infants fed the LCP enriched formula had significantly higher LCP proportions in plasma lipids than infants given the conventional formula, but less than infants fed human milk. Our results demonstrate that small concentrations of dietary LCP have marked effects on plasma lipid composition, particularly on phospholipids, suggesting that dietary LCP are preferentially channelled into structural lipids. We conclude that the essential fatty acid status of formula-fed premature infants can be improved by a supplementation of omega-6- and omega-3-LCP.