Fatty acid changes in plasma lipids and lymphocyte phospholipids after infusion of intralipid to newborn infants.

The fatty acid composition of the major plasma lipids and blood lymphocyte phospholipids was studied in four patients before and after 1 month of parenteral nutrition including 2 to 3 g/kg/day of Intralipid fat and in four matched controls before and after 1 month of breast-feeding. After treatment with Intralipid the concentration of polyunsaturated fatty acids including linoleic acid increased in all plasma lipids. The total concentration of polyunsaturated fatty acids in lymphocyte phospholipids did not change. The increase of linoleic acid and decrease of arachidonic acid in lymphocyte phospholipids were not statistically significant. In control infants the concentration of polyunsaturated fatty acids including linoleic and arachidonic acid in lymphocyte phospholipids increased after 1 month of breast-feeding to almost the same values as in the patients. The study indicates that at least in lymphocytes the incorporation of polyunsaturated fatty acids is actively regulated. The present way of administering Intralipid does not seem to cause any abnormal fatty acid pattern of the plasma and lymphocyte lipids. The use of intravenous fat emulsion with high content of linoleic acid in term newborns should thus not be expected to result in changes of the physical-chemical properties of membranes and membrane dysfunction.