How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Glutamine
An amino acid highly present in muscles. In the healthy athlete, its claimed benefits are poorly supported; its measured effects concern the gut during exertion and critically ill patients.
Benefits
- Prevents the gut from becoming more permeable during intense exertion, after a pre-exercise intake or 7 days of intake
- In critically ill patients, reduces the length of hospital stay and, by infusion, infectious complications (meta-analyses of randomized trials)
- In very low birth weight infants, via the digestive tract, fewer hospital-acquired blood infections and better meal tolerance
Precautions
Caution in case of liver or kidney disease. Also worth knowing: in the healthy athlete, the claimed benefits (immunity, glycogen, anti-catabolic effect) are poorly supported by well-controlled studies; after a marathon, it did not modify the white blood cell distribution of runners. Against mouth inflammations due to chemotherapy, 16 g per day for 8 days changed nothing, and in premature infants, glutamine by infusion reduced neither mortality nor infections.
Recommended dosage
No dose is studied for the athlete in this profile; one-off doses of 20 to 30 g are well tolerated. In the hospital, 20 to 25 g per day.
How to take it
- For the athlete: the claimed benefits (immunity, glycogen, anti-catabolic effect) are poorly supported in a healthy person, according to the review dedicated to its dosage in athletes.
- What has a measured effect: an intake before intense exertion, or 7 days of intake, prevented the gut from becoming more permeable during exertion.
- Tolerance: one-off doses of 20 to 30 g are generally well tolerated.
- In the hospital, it is a different matter: the measured benefits concern critically ill patients, often by infusion, around 20 to 25 g per day.
Did you know?
Glutamine supplementation may prevent the increase in intestinal permeability (leaky gut syndrome) caused by intense exercise, an effect linked to the activation of protective proteins such as HSP70.
What the studies say
This systematic review and meta-analysis evaluated enteral glutamine supplementation in critically ill patients. It found no significant benefit on hospital mortality, infectious complications, or length of stay in the intensive care unit. However, a significant reduction in the length of hospital stay was observed, with potential benefit for burn patients requiring further research.
van Zanten AR, Dhaliwal R, Garrel D, Heyland DK. — Critical care (London, England) (2015) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more