Effects of intravenous supplementation with alpha-tocopherol in patients receiving total parenteral nutrition containing medium- and long-chain triglycerides.

OBJECTIVE: To compare the effects of a lipid emulsion containing medium-chain triglycerides (MCT) and supplemented with alpha-tocopherol to a conventional long-chain triglyceride (LCT) emulsion. DESIGN: Randomised double blind study. SETTING: Department of Internal Medicine, Antwerp University Hospital. SUBJECTS AND INTERVENTIONS: Twenty-four patients with an indication for total parenteral nutrition for a minimum of 10 days were randomly assigned to two groups: group E received as lipid source MCT/LCT (50/50) suplemented with 100 mg DL-alpha-tocopherol/day and group C received LCT. Blood samples were analysed at inclusion, after 4-6 and after 9-11 days. RESULTS: In group E, serum alpha-tocopherol doubled from 11.4+/-6.9 at inclusion to 20.9+/-7.9 and to 23.8+/-8.8 microg/ml after 4 and 9 days, respectively, but did not change in group C (P=0.008). Production of thiobarbituric acid-reacting substances (TBARS) after 120 min incubation with copper decreased from 66+/-34 at inclusion to 29+/-25 nmol MDA/mg LDL and VLDL-cholesterol after 4 and to 42+/-17 after 9 days (P=0.022 when compared to group C, which underwent no significant changes). Velocity of production of fluorescent products decreased in group E but not in group C (P=0.026). CONCLUSIONS: Supplementation of TPN containing MCT/LCT with 100 mg DL-alpha-tocopherol/day leads to a doubling in serum alpha-tocopherol and to a decrease in the susceptibility of LDL and VLDL to peroxidation in vitro. SPONSORSHIP: This study was partly financed by B Braun Medical NVSA, Diegem, Belgium.