Plasma and Red Blood Cell Vitamin E Status of Patients on Total Parenteral Nutrition

Abstract

Plasma and red blood cell (RBC) tocopherol isomer (α, β, δ, and γ) concentrations were measured prior to, and following total parenteral nutrition (TPN), with Intralipid. Before feeding, nine of 13 patients had plasma total tocopherol levels < 0.6 mg/dl (normal range 0.63-1.24 mg/dl) and 10 of 13 had total RBC tocopherol levels less than 0.2 mg/dl (normal range (0.20-0.39 mg/dl). Following 7 days TPN plasma vitamin E status increased significantly (p < 0.001). However, this was due mostly to increases in the circulating level of β + γ-tocopherols. RBC vitamin E status was also significantly increased (p < 0.001) following TPN, however, this was again due to incorporation of non-α-tocopherols. In a second study a α-tocopherol supplement, Vitlipid N, (9.1 mg α-tocopherol/ day) was included in the feed. In these patients, large increases in plasma concentrations of non-α-tocopherol isomers were accompanied by an apparent improvement in α-tocopherol status (0.64 us 0.44 mg/dl after 7 days). However, RBC α-tocopherol concentration did not change appreciably in these patients following either 7 or 14 days feeding. It is concluded that RBC vitamin E status is markedly influenced by the available plasma tocopherol pool and that provision of a small supplement of α-tocopherol is not sufficient to compete with the high concentration of non-α-isomers present in Intralipid. TPN utilizing fat emulsions containing high levels of non-α-tocopherol isomers (even when accompanied by α-tocopherol supplements) does not improve α-tocopherol status. (Journal of Parenteral and Enteral Nutrition 13:510-515, 1989)