The Role of Glutamine in the Complex Interaction between Gut Microbiota and Health: A Narrative Review
Department of Biology, College of Science, University of Bahrain, 32038 Sakhir, Bahrain
Endocrinology and Nutrition Unit, Azienda di Servizi alla Persona ‘‘Istituto Santa Margherita’’, University of Pavia, Pavia 27100, Italy
Department of Biomedical Science and Human Oncology, University of Bari, Bari 70121, Italy
Research and Development Department, Indena SpA, 20139 Milan, Italy
IRCCS Mondino Foundation, Pavia 27100, Italy
Department of Public Health, Experimental and Forensic Medicine, Unit of Human and Clinical Nutrition, University of Pavia, Pavia 27100, Italy
Author to whom correspondence should be addressed.
The two authors contributed equally to this work.
Int. J. Mol. Sci. 2019, 20(20), 5232; https://doi.org/10.3390/ijms20205232
Received: 21 August 2019 / Revised: 16 October 2019 / Accepted: 20 October 2019 / Published: 22 October 2019
(This article belongs to the Special Issue Glutamine: An Essential Non-Essential Amino Acid)
The scientific literature has demonstrated that glutamine is one of the main beneficial amino acids. It plays an important role in gut microbiota and immunity. This paper provides a critical overview of experimental studies (in vitro, in vivo, and clinical) investigating the efficacy of glutamine and its effect on gut microbiota. As a result of this review, we have summarized that glutamine could affect gut microbiota via different mechanisms including the reduction in the ratio of Firmicutes to Bacteroidetes, with the activation of NF-κB and PI3K-Akt pathways, reducing the intestinal colonization (Eimeria lesions) and bacterial overgrowth or bacterial translocation, increasing the production of secretory immunoglobulin A (SIgA) and immunoglobulin A+ (IgA+) cells in the intestinal lumen, and decreasing asparagine levels. The potential applications of glutamine on gut microbiota include, but are not limited to, the management of obesity, bacterial translocation and community, cytokines profiles, and the management of side effects during post-chemotherapy and constipation periods. Further studies and reviews are needed regarding the effects of glutamine supplementation on other conditions in humans.