NUTRITION AND THE INTENSIVE CARE UNIT: Edited by Peter J.M. Weijs and Stephen A. McClaveVitamin C supplementation in the critically ill patientBerger, Mette M.a; Oudemans-van Straaten, Heleen M.bAuthor Information aAdult Intensive Care and Burns, University Hospital CHUV, Lausanne, Switzerland bDepartment of Intensive Care, VU University Medical Center, Amsterdam, the Netherlands Correspondence to Mette M. Berger, Service of Adult Intensive Care and Burns, CHUV BH 08.612, Rue du Bugnon 46, 1011 Lausanne, Switzerland. Tel +41 21 31 42 095; e-mail: [email protected] Current Opinion in Clinical Nutrition and Metabolic Care: March 2015 - Volume 18 - Issue 2 - p 193-201 doi: 10.1097/MCO.0000000000000148 Buy Metrics Abstract Purpose of review Vitamin C is not only an essential nutrient involved in many anabolic pathways, but also an important player of the endogenous antioxidant defense. Low plasma levels are very common in critical care patients and may reflect severe deficiency states. Recent findings Vitamin C scavenges reactive oxygen species such as superoxide and peroxynitrite in plasma and cells (preventing damage to proteins, lipids and DNA), prevents occludin dephosphorylation and loosening of the tight junctions. Ascorbate improves microcirculatory flow impairment by inhibiting tumor-necrosis-factor-induced intracellular adhesion molecule expression, which triggers leukocyte stickiness and slugging. Clinical trials in sepsis, trauma and major burns testing high-dose vitamin C show clinical benefit. Restoration of normal plasma levels in inflammatory patients requires the administration of 3 g/day for several days, which is 30 times the daily recommended dose. Summary The recent research on the modulation of oxidative stress and endothelial protection offer interesting therapeutic perspectives, based on the biochemical evidence, with limited or even absent side-effects. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.