Vitamin status during total parenteral nutrition.

Plasma concentrations of vitamins A and E, serum and erythrocyte folic acid, serum B12 and erythrocyte enzyme activations (to assess vitamins B1, B2 and B6 status) were measured at the start and finish of 39 courses of total parenteral nutrition (TPN). The daily regimen was standard. Plasma vitamin A, E, and folate concentrations and vitamin B6 status improved significantly during TPN. Three patients developed low levels of vitamin A and two patients developed high transketolase activations (B1 depletion) during therapy. The adequacy of vitamin replacement and the monitoring of vitamin status during TPN is discussed.