The Role of Glutamine in the Complex Interaction between Gut Microbiota and Health: A Narrative Review.

Plain Language Summary

Glutamine is an amino acid, one of the building blocks of protein, and is the most abundant free amino acid in the body. Research shows that glutamine plays an important role in digestive health and immunity by supporting the integrity of the intestinal lining and suppressing inflammation. This review looks at glutamine and its mechanism on gut microbiota; the commensal bacteria which populate the gastro-intestinal tract. Glutamine supplementation was shown to beneficially affect the composition of gut bacteria in obese and overweight subjects, reduce bacterial overgrowth and more specifically reduce harmful strains of Clostridium spp. and Helicobacter spp. The subsequent increase in intestinal-friendly microbiota after supplementation aided symptoms of constipation. This same mechanism may help prevent bacterial infections in chemotherapy cancer patients which is a common side effect of the treatment. Glutamine also supports immune cell activity. White blood cells were shown to use a four-fold amount of glutamine versus glucose. There are indications of glutamine-mediated crosstalk between intestinal microbes and the immune system and that glutamine appears to be helpful in patients with severe digestive disturbances as well as metabolic stress, trauma, infection, burns and muscle-wastage.