Key points
- Glutamine can reduce intestinal permeability (‘leaky gut’)
- Glutamine can be useful in the adjunctive treatment of inflammatory bowel diseases
- High doses are typically required (upwards of 20 g per day)
Glutamine is commonly used in ‘gut-healing’ protocols by allied and complementary healthcare practitioners. It is suggested that glutamine aids the integrity and health of the gut by providing fuel for intestinal epithelial cells, protect the intestinal mucosa, improve intestinal permeability (leaky gut), and reduce bacterial translocation and endotoxin damage.1, 2
Research over the last ten years has shown the following:
- Glutamine supplementation at a dosage of 0.9 g/kgLBM per day of glutamine reduced exercise-induced intestinal permeability and reduced plasma endotoxins.3
- 20-30 g of glutamine per day are likely to reduce symptoms of inflammatory bowel diseases.2
- In a randomised, placebo-controlled trial, 20 g of glutamine per day (for 7 days) reduced endotoxaemia and inflammation (c-reactive protein).4
- Supplementation with 30 g glutamine per day has been shown to reduce the Firmicutes to Bacteroidetes ratio with an effect similar to that induced by weight loss.5
What does this all mean?
Glutamine has a known functional role in fuelling the cells of the intestinal wall which utilise glutamine as a priority fuel source.
It is also clear based on the extant research that glutamine does help to improve intestinal permeability (thus reducing systemic inflammation) and might also aid the integrity of the microbiome. However, the dosages used to support gut health in the research are very high (>20 g per day) which anecdotally may cause GI distress in some people and can be cost-prohibitive. In addition, many supplements designed to support gut health contain only token amounts of glutamine unlikely to promote a therapeutic effect and unlikely to offer any additional benefits over normal dietary intakes of glutamine.
If using glutamine to support health, it is suggested that at least 20 g per day is taken, in divided doses, for example, 1 teaspoon – 4 x per day.
References
1. Lin Y. Glutamine and gut barrier function: underlying mechanisms and clinical application. International Journal of Pediatrics. 2017;44(6):385-8.
2. Irvin L, Heuberger R. Enhancing gut function and providing symptom relief in IBD with glutamine supplementation: a literature review. Gastrointestinal Nursing. 2015;13(6):26-34.
3. Zuhl MN. The effects of oral glutamine supplementation on gut permeability and heat shock protein regulation among runners with a history of gastrointestinal distress: The University of New Mexico; 2012.
4. Singh N, Mishra SK, Sachdev V, Sharma H, Upadhyay AD, Arora I, et al. Effect of Oral Glutamine Supplementation on Gut Permeability and Endotoxemia in Patients With Severe Acute Pancreatitis: A Randomized Controlled Trial. Pancreas. 2014;43(6).
5. Zambom de Souza AZ, Zambom AZ, Abboud KY, Reis SK, Tannihão F, Guadagnini D, et al. Oral supplementation with l-glutamine alters gut microbiota of obese and overweight adults: A pilot study. Nutrition. 2015;31(6):884-9.
