Are amino acid injections useful for nutritional support?

From the Guidelines

Amino acid injections are useful for nutrition in specific medical situations, such as critical illness, where they can help meet protein requirements and support tissue repair, with a recommended dose of 1.3-1.5 g/kg ideal body weight per day, as indicated by the ESPEN guidelines on parenteral nutrition 1.

Key Considerations

• The primary goal of amino acid administration in critical illness is to provide precursors for protein synthesis and protect skeletal muscle mass and function, as noted in the ESPEN guidelines 1.
• A balanced amino acid mixture should be infused in conjunction with an adequate energy supply to achieve optimal protein synthesis stimulation, as recommended by the ESPEN guidelines 1.
• The optimal whole body protein sparing effects are achieved when amino acids are infused at mean rates of 1.3 and 1.5 g/kg/day in trauma or sepsis, respectively, with no further advantages observed when more amino acids are provided, as demonstrated in studies cited in the ESPEN guidelines 1.

Clinical Applications

• Amino acid injections are primarily used in clinical settings for patients who cannot obtain adequate nutrition through normal eating or enteral feeding, such as those with severe malabsorption disorders, certain gastrointestinal diseases, or patients requiring total parenteral nutrition (TPN) 1.
• The dosage of amino acid injections varies based on individual patient needs, body weight, and medical condition, with the ESPEN guidelines providing recommendations for critical illness 1.
• Amino acid injections can help maintain protein synthesis, immune function, and tissue repair when normal nutrition is compromised, as noted in the ESPEN guidelines 1.

Important Notes

• For healthy individuals or those who can eat normally, obtaining amino acids through dietary protein is more physiological, safer, and less expensive than injections, as amino acid injections bypass the digestive system's regulatory mechanisms and can potentially cause imbalances or adverse reactions 1.
• The ESPEN guidelines on parenteral nutrition provide recommendations for amino acid administration in critical illness, emphasizing the importance of a balanced amino acid mixture and adequate energy supply 1.

From the Research

Amino Acid Injections for Nutrition

• Amino acid injections can be useful for nutrition, particularly in certain medical conditions where oral intake is not possible or sufficient 2, 3.
• Studies have shown that intravenous supplementation of amino acids can positively affect protein metabolism in severely malnourished cancer patients 2 and critically ill patients 3.
• The optimal dose of amino acids to administer is not well established, but research suggests that higher quantities may be beneficial for cancer patients 2 and critically ill patients 3.
• Amino acid injections can help sustain a positive protein balance for 24 hours in critically ill patients 3.
• Parenteral amino acid therapy can achieve the goal of delivering a generous amount of protein without a toxic amount of energy to protein-catabolic critically ill patients 4.
• Enteral nutrition supplemented with specific amino acids can also have a positive effect on protein metabolism in polytrauma patients 5.
• The type and amount of amino acids used can vary depending on the specific medical condition and nutritional needs of the patient 2, 5, 3, 4.