Serum vitamin level maintenance in cancer patients on total parenteral nutrition.

The quantity of water and fat soluble vitamins required to maintain serum levels in cancer patients on total parenteral nutrition (TPN) has yet to be determined. A prospective evaluation of our current intravenous vitamin regimen during TPN was performed in order to define these requirements. Seventy-five patients receiving 97 TPN courses for seven to 60 days were studied. Serum levels of vitamins A (74 courses), B12 (85), folate (62), C (97), and 25-OH-cholecalciferol (25-OH-D) (9) were available for analysis. Daily vitamin intakes were recorded and serum levels were determined weekly. Restoration and maintenance of normal mean serum vitamin levels were achieved for all but 25-OH-D. However, analysis of individual courses in previously depleted patients revealed that serum levels were not restored in three patients (4%) for vitamin A and six patients (66%) for 25-OH-D. A TPN regimen designed to provide the following weekly vitamin quantities: A: 21,000 IU, D: 2100 IU, C: 3500 mg, B12: 126 micrograms, and folate: 7 mg will maintain mean serum vitamin levels for all but 25-OH-D. This regimen has the ability to uniformly restore and maintain vitamins B12, C, and folate in all patients but not in those patients previously deficient in vitamins A and D.