In both preterm neonates and adults,parenteral administration oflipid emulsions caused increased lipid peroxidation.This is manifested as increased breath pentane,and increased malonedialdehyde or thiobarbituric acid reactant substances in plasma and body tissues.Such peroxidative reactions have been implicated as the cause of cellular and tissue damage in adults and infants.Avoiding the use of lipid emulsions in critically ill TPN patients is not really a practical approach to avoid peroxidative damage as a mixed glucose-fat fuel system has been shown to be superior to a glucose-based regimen.A viable alternative is to supplement parenteral supply of lipids with antioxidants like α-tocopherol.The involvement of antioxidants in proxidation reactions has been implicated by findings of negative correlation between plasma α-tocopherol level and breath pentane output as well as a negative correlation between plasma α-tocopherol level and duration of home parenteral nutrition (Lemoyne et al.,1988).It has also been demonstrated that intravenous supplementation of Vitamin E counteracted LCT-induced peroxidation and prevented Vitamin E depletion (Wispe et al.,1986,Pitkanen et al,1991,Siderovaet al.,1995).The extent of peroxidation is influenced not only by enrichment with α-tocopherol in the emulsion,but also by the composition of the fat emulsion also.Thus,the lower PUFA content of MCT/LCT lipid emulsion compared to pure LCT emulsions caused less peroxidation (Zimmermann et al.,1993,Arorati et al.,1997).In summary,reduction of susceptibility of fat emulsion to peroxidation can be achieved by reducing the content of unsaturated fatty acid by using a mixed emulsion like a physical mixed MCT/LCT lipid emulsion and supplementing the lipid emulsion with Vitamin E.