Vitamin C Supplementation of Total Parenteral Nutrition Formulas

Abstract

The effect of a wide range of daily vitamin C intake (350-2250 mg, mean 975 mg) on the serum and urine vitamin C levels was studied in 20 adult hospitalized patients receiving total parenteral nutrition for a period greater than 15 days. Serum vitamin C levels increased with vitamin C administration, but remained within the normal range. Urine vitamin C levels were above normal during total parenteral nutrition in all but one patient. A positive vitamin C "balance" was achieved in all patients. The vitamin C intake positively correlated with the vitamin C urine concentration and vitamin C "balance." Maximal vitamin C retention was 800 mg/day. It is concluded that administration of vitamin C in doses greater than 1000 mg/day is unjustified in those patients receiving total parenteral nutrition who are not hypermetabolic.

Hypovitaminosis C and vitamin C deficiency in critically ill patients despite recommended enteral and parenteral intakes

“…However, hypovitaminosis C was not prevented in our patients with the use of standard enteral and/or parenteral nutrition, despite our TPN containing additional vitamin C (i.e., a total of nearly 200 mg/L). These results agree with data reported by others who have shown that parenteral intakes of ~ 300 mg/day did not change their patients’ plasma vitamin C concentrations [ 13 , 27 ]. In comparison, intakes of 150–200 mg/day will saturate the plasma of healthy individuals [ 23 ], although we and others have observed decreased response to supplementation in individuals with hypovitaminosis C [ 48 , 49 ].…”

“…There are a number of possible explanations for the discrepancy in predicted and measured vitamin C concentrations. It is possible that enteral and parenteral preparations contain less vitamin C than stated, owing to the instability of the vitamin in the presence of oxygen, transition metal ions, ultraviolet light and higher temperatures [ 27 , 28 ]. Furthermore, critically ill patients are at significant risk for gastrointestinal dysfunction and consequently poor absorption for those patients who receive enteral feeding [ 29 ].…”

“…Uncomplicated surgical patients require > 500 mg/day of vitamin C, with much higher doses required in surgical ICU patients [ 50 ]. Parentaeral administration of ≥ 1000 mg/day vitamin C to critically ill patients was barely sufficient to raise plasma vitamin C concentrations above hypovitaminosis C levels [ 13 , 27 ]. Recent pharmacokinetic data in critically ill patients indicate that ≥ 2000 mg/day is required to normalise plasma vitamin C levels [ 51 ], and 3000 mg/day has been shown to result in saturating levels (i.e., 68 μmol/L), as evidenced by enhanced urinary excretion [ 13 ].…”

Compatibility and Stability of TPN Mixtures in Big Bags

“…It should also be noted that one degradation product of vitamin C oxidation is oxalic acid which may be present in clinically significant quantities if considerable amounts of vitamin C have degraded. The need to ensure that adequate doses of vitamin C are administered has recently been highlighted (53).…”