Since publishing our clinical brief on illness anorexia (Alcock and Legrand 2014), described in the last entry on this blog, a recent trial examined whether giving intensive nutrition to critically ill patients with lung injury helps survival. Based on what we have proposed in EMPH and also the idea of immune brinksmanship, we would predict that intensive feeding would be harmful.
Braunschweig and colleagues (2015) studied whether intensive nutrition (attempting to replace most calorie and nutrient needs) improves survival in ICU patients with acute lung injury compared to standard nutrition, in which patients receive less. These patients are intubated and cannot eat, so physicians and nutritionists make feeding decisions for them. Nutritionists can calculate how many calories the body needs, and many advocate for full replacement. However, because gut motility is often impaired in critical illness, most patients receive less than calculated needs in current practice.
The bottom line: This study was terminated early for increased deaths in the intensive feeding group. Trying to normalize calorie replacement kills critically patients with ALI.
From the abstract:
“Background: Despite extensive use of enteral (EN) and parenteral nutrition (PN) in intensive care unit (ICU) populations for 4 decades, evidence to support their efficacy is extremely limited.
Methods: A prospective randomized trial was conducted evaluate the impact on outcomes of intensive medical nutrition therapy (IMNT; provision of >75% of estimated energy and protein needs per day via EN and adequate oral diet) from diagnosis of acute lung injury (ALI) to hospital discharge compared with standard nutrition support care (SNSC; standard EN and ad lib feeding). The primary outcome was infections; secondary outcomes included number of days on mechanical ventilation, in the ICU, and in the hospital and mortality.
Results: Overall, 78 patients (40 IMNT and 38 SNSC) were recruited. No significant differences between groups for age, body mass index, disease severity, white blood cell count, glucose, C-reactive protein, energy or protein needs occurred. The IMNT group received significantly higher percentage of estimated energy (84.7% vs 55.4%, P < .0001) and protein needs (76.1 vs 54.4%, P < .0001) per day compared with SNSC. No differences occurred in length of mechanical ventilation, hospital or ICU stay, or infections. The trial was stopped early because of significantly greater hospital mortality in IMNT vs SNSC (40% vs 16%, P = .02). Cox proportional hazards models indicated the hazard of death in the IMNT group was 5.67 times higher (P = .001) than in the SNSC group.
Conclusions: Provision of IMNT from ALI diagnosis to hospital discharge increases mortality.” (emphasis added).
So dear reader, you decide. Is this result predictable by evolutionary medicine? What do you suppose will be the result of future similar feeding trials?
Excellent additional reading: Preiser, Jean-Charles, et al. Metabolic and nutritional support of critically ill patients: consensus and controversies. Critical Care 19.1 (2015): 35.
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Joe Alcock
Emergency Physician, Educator, Researcher, interested in the microbiome, evolution, and medicine
EvolutionMedicine 
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