University of Virginia Nutrition
Well, winter is here in the Shenandoah Valley. We had very mild weather last week; it felt like Spring with temperatures in the 60’s during the day. This week it has turned quite cold, and even though we were overdue for cold weather the rapid transition was a shock. Theresa Fessler led the journal club this month; an article on antioxidant micronutrient supplementation in the ICU.
Crimi E, Liguori A, Condorelli M, Cioffi M, Astuto M, Bontempo P, Pignalosa O, Vietri MT, Molinari AM, Sica V, Della Corte F, Napoli C. The beneficial effects of antioxidant supplementation in enteral feeding in critically ill patients: a prospective, randomized, double blind, placebo-controlled trial. Anesth Analg 2004; 99: 857-863
The primary end-point was measure of oxidative stress (malonydialdehyde-TBARS, PGF2a, LDL tocopherol, and LDL oxidation. Secondary end-points were infection, multi-organ failure, duration of ventilation, Vent-free days, 28 day outcome, and hospital length of stay.
This study confirms previous work that antioxidant supplements decrease oxidative markers in critically ill patients (1). More importantly, it provides outcome data - significant improvement in mortality in this critically ill population.
However, without any significant change in organ failure, ARDS, or infectious complications, it is unclear why these patients had a mortality improvement. Perhaps it can be considered that there was an improvement in pulmonary organ failure, as evidenced by the reduced ventilator requirements in the antioxidant group. The improvements in pulmonary function are consistent with another study that we had reviewed (2) that reported decreased pulmonary morbidity (ARDS and pneumonia) with a combination of vitamin C and E. A very recent meta-analysis reported favorably on antioxidant supplementation in critically ill patients – decreased overall morbidity without a significant change in infectious complications (3).
This is a well designed study, with very interesting findings, but there is no way to be sure if both micronutrients are necessary, or what is the optimal dose or form of antioxidants. The meta-analysis (3) describes positive outcomes with selenium supplementation. Considering the complementary physiologic action of vitamin E, vitamin C and selenium, there should be a study to determine if there are additional benefits of a combination of antioxidants. This study is certainly not large enough to be sure that there is no potential for adverse reactions of some pharmaconutrients in some critically ill populations. The immunonutrition studies should be the lesson that nutritional interventions in the critically ill population need to be treated with the same level of investigational rigor and repeatability as any other medical intervention.
Take home message:
1) Preiser JC, Van Gossum A, Berre J, Vincent JL, Carpentier Y. Enteral feeding with a solution enriched with antioxidant vitamins A, C, and E enhances the resistance to oxidative stress. Crit Care Med. 2000 Dec;28(12):3828-32.
2) Nathens AB, Neff MJ, Jurkovich GJ, Klotz
P, Farver K, Ruzinski JT, Radella F, Garcia I, Maier RV.
Randomized, prospective trial of antioxidant supplementation in
critically ill surgical patients. Ann Surg. 2002
"The aim of argument, or of discussion, should not be victory....but progress."
Joe Krenitsky MS, RD
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