Amino Acids

Acute kidney injury (AKI) is a frequent complication of cardiac surgery, contributing to increased morbidity, longer hospital stays, and higher mortality. Evidence suggests amino acid (AA) supplementation may enhance renal blood flow and glomerular filtration rate (GFR), potentially reducing AKI risk; however, findings remain inconclusive. This study evaluated the efficacy of perioperative AA supplementation in preventing AKI and related complications post‐cardiac surgery.

PubMed, Embase, and Cochrane databases were searched for randomized controlled trials (RCTs) comparing AA supplementation versus standard care in preventing cardiac surgery‐associated AKI. Main outcomes included AKI incidence (defined by the Kidney Disease Improving Global Outcomes (KDIGO) criteria), 30‐day mortality, and renal replacement therapy (RRT) requirement. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were calculated using random‐effects models. Statistical significance was set at p < 0.05. The certainty of the evidence (CoE) was assessed using the GRADE approach.

Six RCTs involving 4501 cardiac surgery patients were included. AA mixture interventions significantly reduced the risk of AKI stage 1 (RR: 0.56; 95% CI: 0.77–0.96; p = .009; CoE: Moderate) and Stage 3 (RR: 0.53; 95% CI: 0.34–0.83; p = .005; CoE: Moderate), but not stage 2 (RR: 1.24; 95% CI: 0.60–2.55; p = .568; CoE: Low). Preliminary findings from glutamic acid and glutamine (single AA interventions) showed potential benefits in reducing AKI incidence (CoE: Very low) and improving surrogate biomarkers, respectively. No significant effects were observed on mortality or RRT incidence for any intervention.

AA mixtures likely reduce AKI incidence following cardiac surgery but show limited effects on mortality and RRT. Further trials are needed to confirm the benefits of glutamic acid and glutamine supplementation.

Use of amino acid supplementation for the prevention of acute kidney injury after cardiac surgery may be effective, but more trial data and confidence in a beneficial effect is needed for this to be implemented in everyday clinical practice.

Background/Objectives: Weight loss interventions in individuals with overweight or obesity result in reductions in both fat mass and lean body mass (LBM). While fat loss is the primary therapeutic target, preserving LBM may have favorable health implications. This narrative review evaluates the role of amino acid supplementation, including essential amino acids (EAAs) and branched-chain amino acids (BCAAs), in supporting the preservation of LBM during weight loss induced by lifestyle interventions, pharmacotherapy, or bariatric surgery. Methods: This is a narrative review of preclinical and clinical studies examining the effects of amino acid supplementation during calorie restriction on body composition and, when available, functional outcomes. A comprehensive search was conducted in the PubMed, Scopus, and Web of Science databases. Results: Evidence suggests that EAA and peptide-based supplementation may help preserve LBM during periods of reduced energy intake, particularly when protein intake from whole foods is limited. Benefits appear more consistent when supplementation is combined with resistance exercise. BCAA supplementation alone has shown variable effects, especially in sedentary individuals or when total protein intake is already sufficient. Anabolic resistance associated with obesity may attenuate the muscle protein synthesis response to dietary amino acids. Conclusions: Amino acid supplementation may support the maintenance of LBM during weight loss, particularly under conditions of low protein intake or in conjunction with exercise. Further research is needed to determine the clinical significance of LBM changes and identify optimal supplementation strategies.