Tocopherol Isomers in Intravenous Lipid Emulsions and Resultant Plasma Concentrations

Abstract

Conflicting reports exist regarding the relative tocopherol isomer content of Intralipid ranging from 99% as α-tocopherol to as much as 90% as γ-tocopherol. Our direct assay of Intralipid as well as plasma levels measured in premature infants receiving Intralipid confirm the existence of a low α, high γ-tocopherol content and imply the need for α-tocopherol supplementation in patients receiving Intralipid, particularly the relatively tocopherol-deficient premature infant. Furthermore, the observation of abnormal erythrocyte hemolysis test values despite "normal" total tocopherol plasma concentrations may be explained by high plasma levels of non-α, biologically less active isomers. The quantitation of tocopherol isomers helps explain this discrepancy and suggests the need for future studies of vitamin E status to employ measurements of tocopherol isomers in reporting results. (Journal of Parenteral and Enteral Nutrition 8:269-273, 1984)