High-Protein Supplementation in Critically Ill Patients: A Systematic Review, Meta-Analysis and Umbrella Review of Existing Evidence

Why It Matters

The findings challenge the assumption that higher protein automatically improves outcomes, urging clinicians to reconsider dosing strategies and avoid extended high‑protein feeding in the ICU.

Key Takeaways

• High-protein (≥1.2 g/kg/day) shows no mortality benefit overall
• Long-term (>14 days) high protein may modestly raise mortality risk
• Short-term high protein can shorten hospital stay by ~2.7 days
• ICU stay reduced only in low/medium‑risk patients receiving high protein
• No significant differences in ventilation time or infection rates

Pulse Analysis

Critically ill patients experience rapid muscle catabolism, prompting clinicians to prescribe protein doses well above traditional recommendations. Yet consensus on the optimal amount remains elusive, with guidelines ranging from 0.8 to 2.0 g/kg/day. This new umbrella review consolidates the latest randomized evidence, expanding the sample size and applying rigorous trial sequential analysis to assess whether higher protein intake translates into tangible clinical gains.

The meta‑analysis confirms that, across 3,502 patients, high‑protein supplementation does not reduce overall mortality or improve key ICU metrics such as ventilation duration. Notably, a subgroup of trials extending protein provision beyond two weeks showed a slight but statistically significant increase in mortality, suggesting that prolonged excess protein may overwhelm metabolic pathways, exacerbate renal stress, or impair autophagy. Conversely, short‑term high‑protein feeding (≤14 days) was associated with a modest reduction in hospital length of stay, hinting at potential benefits in the acute recovery phase when nitrogen balance is most critical.

For practitioners, the evidence advises a balanced approach: prioritize meeting baseline protein needs without exceeding 1.2 g/kg/day for extended periods, especially in patients with renal impairment or high nutritional risk. Future research should target disease‑specific cohorts, integrate real‑time protein intake monitoring, and explore biomarkers that predict individual tolerance. Until such data emerge, ICU nutrition protocols are likely to favor moderate protein targets, reserving higher doses for brief, carefully monitored intervals.