Parenteral nutrition in overweight patients: are intravenous lipids necessary to prevent essential fatty acid deficiency?

Abstract

Mobilization of endogenous adipose stores of linoleic acid prevents essential fatty acid deficiency during fasting. However, the dextrose present in standard parenteral nutrition inhibits lipolysis and induces essential fatty acid deficiency unless lipids are administered. It has therefore become standard practice to administer at least 50 grams of intravenous fat per week to patients dependent on parenteral nutrition. This study was undertaken to determine whether hypocaloric feeding would permit sufficient mobilization of linoleic acid from adipose tissue stores to prevent essential fatty acid deficiency in overweight cancer patients receiving fat-free parenteral nutrition. Fifteen patients (mean 127% ideal body weight) received continuous infusions of hypocaloric, fat-free parenteral nutrition for 14 to 58 days (median 30 days). Twelve patients lost weight during the study period, while no patient gained more than 5 kg. Changes in serum albumin were mild. Six patients required insulin for hyperglycemia; however, four of these patients had reductions in their insulin requirement despite continuation of parenteral nutrition. Fatty acid analyses were performed on plasma phospholipids from all 15 patients. No patient developed plasma evidence of essential fatty acid deficiency. In addition, no trend toward the development of essential fatty acid deficiency was observed with increasing durations of fat-free parenteral nutrition. Conclusion: Overweight cancer patients can tolerate prolonged, continuous infusions of hypocaloric, fat-free parenteral nutrition without developing essential fatty acid deficiency. This approach appears to reduce both the toxicity and the expense of parenteral nutrition.