From the Guidelines
Glutamine is a non-essential amino acid that serves multiple important functions in the body, and the correct options are (a), (b), and (d).
Key Points
- Glutamine is commonly supplied in total parenteral nutrition formulations to support patients who cannot receive adequate nutrition through the gastrointestinal tract 1.
- It plays a crucial role in maintaining intestinal health by increasing intestinal cellularity, promoting the growth and repair of intestinal cells, and supporting the gut mucosal barrier 1.
- Additionally, glutamine serves as an important substrate for gluconeogenesis, particularly during periods of stress or illness when the body needs to produce glucose from non-carbohydrate sources 1.
- While glutamine is vital for many physiological processes, it is classified as a non-essential amino acid because the body can synthesize it under normal conditions, primarily in skeletal muscle 1.
- However, during severe illness or stress, glutamine may become conditionally essential as the body's demand exceeds its production capacity 1.
Evidence
- A recent meta-analysis included 19 RCTs with 1243 patients scheduled for elective major abdominal surgery, and found that glutamine supplementation did not affect overall morbidity, but patients treated with glutamine had a significant reduction in length of hospital stay 1.
- Another study found that parenteral glutamine supplementation was associated with a trend toward a reduction in overall complications and a significant reduction in hospital length of stay in patients with acute pancreatitis 1.
- The ESPEN guidelines recommend considering parenteral glutamine supplementation in ICU patients, particularly those with severe illness or stress, as it may become conditionally essential in these situations 1.
From the Research
Glutamine Properties and Functions
- Glutamine is supplied in total parenteral nutrition, as stated in 2 and 3, which highlights its importance in critical care therapy and maintaining intestinal integrity.
- Glutamine increases intestinal cellularity, as shown in 4, where glutamine dipeptide-supplemented parenteral nutrition maintained intestinal function in critically ill patients.
- Glutamine is considered a conditionally essential amino acid, as mentioned in 2 and 5, due to its increased demand during critical illness and its role in maintaining intestinal integrity and immune function.
- Glutamine can be a substrate for gluconeogenesis, although this is not directly stated in the provided studies, it is known that glutamine can be converted to glucose through gluconeogenesis in certain situations.
Clinical Relevance of Glutamine Supplementation
- Glutamine supplementation is recommended for immune-suppressed individuals and those in catabolic/hypercatabolic situations, as discussed in 5.
- The beneficial effects of glutamine supplementation on immune function and intestinal integrity are established, but more research is needed to determine its effects in various clinical situations, as mentioned in 5 and 6.
- Glutamine supplementation can improve gut barrier function in experimental conditions of injury and in some clinical situations, as reported in 6.