- Structured lipid emulsion, an innovative approach in which both medium-chain and long-chain fatty acids are esterified to the same glycerol backbone, has been recently shown to be a safe and efficient way of providing energy to patients requiring parenteral nutrition. As yet, no assessment has been made of its safety and effect on liver functions during long-term treatment. Twenty-two home parenteral nutrition patients with Crohn’s disease or short bowel syndrome were enrolled in a double-blind randomized, cross-over study. Twenty patients who completed the study were treated for 4 wk with a structured lipid emulsion and for 4 wk with long-chain triacylglycerol emulsion. Determined every 1 or 2 wk were blood pressure, body weight, respiratory rate, blood count, liver functions, albumin, transferrin, plasma lipids, free fatty acids (FFAs), and, at the end of each treatment period (weeks 4 and 8), plasma dicarboxylic acids and 3-OH-fatty acids. No differences were observed between the groups or within the groups between the two treatments with respect to either clinical safety and adverse event occurrence or laboratory assessments. Plasma dicarboxylic acids and 3-OH-fatty acids were similar and within normal range. No alteration of liver function occurred in any of the patients treated with the structured lipid emulsion, whereas two of the patients receiving long-chain triaclyglycerol emulsion developed abnormal liver function, which resolved after switching to the structured lipid emulsion. In conclusion, structured triacylyglycerols containing both medium- and long-chain fatty acids appear to be safe and well tolerated on a long-term basis in patients on home parenteral nutrition, and it may be associated with possible reduction in liver dysfunction.