Nutritional Recommendations for Patients with Acute Kidney Injury
Patients with acute kidney injury (AKI) require specific nutritional interventions that should NOT follow standard low-protein recommendations typically used for stable chronic kidney disease patients.
Energy Requirements
- Energy intake: 20-30 kcal/kg/day for patients with AKI 1, 2
- Implementation strategy: Progressive implementation to reach target calories by days 3-7 2
- Avoid overfeeding: Initial hypocaloric nutrition (not exceeding 70% of energy expenditure) with gradual increase to 80-100% of measured energy expenditure 1, 2
- Energy assessment: Indirect calorimetry is preferred when available for accurate energy expenditure measurement 2
Protein Requirements
Protein needs vary based on clinical status and renal replacement therapy (RRT):
| Clinical Scenario | Recommended Protein Intake |
|---|---|
| AKI without critical illness, no RRT | 0.8-1.0 g/kg/day [1,2] |
| AKI with critical illness, no RRT | 1.0-1.3 g/kg/day [1] |
| AKI on conventional intermittent RRT | 1.3-1.5 g/kg/day [1] |
| AKI on continuous RRT (CRRT) | 1.5-1.7 g/kg/day [1,2] |
Important principle: Protein prescription should NOT be reduced to avoid or delay RRT initiation in critically ill patients with AKI 1. This is a Grade A recommendation with strong consensus (96% agreement).
Special Considerations
For CKD Patients Who Develop AKI:
- CKD patients previously on controlled protein diets (low protein diets) should discontinue these restrictions during hospitalization for acute illness 1
- The protein need during hospitalization should be guided by the acute illness rather than the underlying CKD condition 1
Micronutrient Supplementation:
- Trace elements: Monitor and supplement selenium, zinc, and copper due to increased requirements during kidney failure and losses during RRT 1
- Water-soluble vitamins: Monitor and supplement vitamin C, folate, and thiamine due to effluent losses during RRT 1
- Daily losses in CRRT effluent: ~68 mg vitamin C, 0.3 mg folate, 4 mg thiamine 1
Metabolic Considerations:
- Critically ill AKI patients oxidize fewer carbohydrates and more lipids than expected 1
- Consider adjusting the ratio of lipids to carbohydrates accordingly
- Account for additional calories from citrate, glucose, and lactate in dialysis/replacement fluids 1, 2
Nutritional Route Preference
- Enteral nutrition should be the preferred route when possible 1, 3
- Parenteral supplementation of amino acids may be required to achieve protein goals, especially in patients on RRT 1, 3
- For enteral nutrition, more concentrated disease-specific (renal) formulas containing 70-80 g protein/L may be preferred to reduce fluid overload 1
Monitoring Parameters
- Regular reassessment of nutritional requirements as patient's condition changes
- Monitor for metabolic complications: hyperglycemia, hypertriglyceridemia, fluid retention, electrolyte imbalances
- Calculate protein catabolic rate when possible, especially in patients on RRT 1
- Use pre-hospitalization or ideal body weight rather than actual weight for calculations in patients with fluid overload 1
Common Pitfalls to Avoid
- Applying chronic kidney disease nutrition guidelines to AKI patients - AKI in acute illness requires higher protein intake than stable CKD
- Restricting protein to delay RRT - This practice worsens nitrogen balance without significant benefit 1
- Using actual body weight for calculations in fluid-overloaded patients - This leads to overestimation of nutritional requirements
- Failing to account for additional calories from dialysis/replacement fluids - This can lead to overfeeding
- Neglecting micronutrient supplementation - Especially important for patients on CRRT due to significant losses
By following these evidence-based recommendations, clinicians can optimize nutritional support for AKI patients to improve outcomes related to morbidity, mortality, and quality of life.