title: A Matter of Fat.
abstract: Acute respiratory disease syndrome (ARDS) is a common complication of critical illness, associated with significant morbidity, prolonged intensive care unit (ICU) and hospital stay, and increased mortality. Inflammation plays a central role in ARDS, with inflammatory eicosanoid mediators produced from the ω-6 fatty acid arachidonic acid, such as leukotriene B4, being involved. The ω-3 fatty acids found in fish oil exert anti-inflammatory effects, including decreasing production of inflammatory eicosanoids from arachidonic acid. The ω-3 fatty acids are effective in models relevant to ARDS. Several randomized controlled trials of enteral formulas rich in ω-3 fatty acids, often in combination with other bioactive substances, have been conducted in patients with ARDS. Four of these trials reported marked clinical benefits, 2 reported no effect, and 1 reported a negative impact. A systematic review and meta-analysis of these 7 trials identified no overall effect on ventilator-free days or on ICU-free days. There was a small reduction in ICU length of stay and no overall effect on mortality. However, the authors formally identified that trials that used high fat in both treatment and control groups showed a significant reduction in mortality, while trials that used a high, or higher, fat treatment and a low-fat control group showed a trend toward an increase in mortality. It is concluded that differences in outcome reported among these studies largely relate to the relative fat contents of the treatment and control formulas. Further, it is concluded that high-fat enteral formulas should not be used in this patient group.
authors.affiliation: Human Development and Health Academic Unit, Faculty of Medicine, University of Southampton, Southampton, UK NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust and University of Southampton, Southampton, UK Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia pcc@soton.ac.uk.
authors.forename: Philip C
authors.initials: PC
authors.lastname: Calder
mesh_terms: D016638:Critical Illness / Q000628:therapy; D015525:Fatty Acids, Omega-3 / Q000627:therapeutic use*; D005395:Fish Oils / Q000627:therapeutic use*; D006801:Humans; D007249:Inflammation / Q000188:drug therapy; D007362:Intensive Care Units; D007902:Length of Stay; D016032:Randomized Controlled Trials as Topic; D012128:Respiratory Distress Syndrome / Q000188:drug therapy*
chemical_list: D015525:Fatty Acids, Omega-3; D005395:Fish Oils
keywords: adult; critical care; enteral formulas; fatty acids; immunonutrition; lipids; pulmonary disease; sepsis; trauma