Oral Supplementation with L-Glutamine Alters Gut Microbiota of Obese and Overweight Human Adults: A Pilot Study
Alessandra Zanin Zambom de Souza Nutrition January 9, 2015; Accepted: January 13, 2015
Highlights
•Oral Supplementation of L-glutamine promotes changes in the gut microbiota composition.
•The Firmicutes/Bacteroidetes ratio decreased after GLN supplementation.
•Firmicutes and Actinobacteria reduced significantly after glutamine supplementation.
•Oral supplementation of L-glutamine has similar effects on gut microbiota as weight loss
The goal of the present study was to determine whether an oral supplementation with L-glutamine modifies the gut microbiota composition in overweight and obese adults.
Methods
Thirty three overweight and obese adults, ages between 23 and 59 and BMI between 25.03 and 47.12 kg/m2, were randomly assigned to either receive oral supplementation with 30g of L-alanine (ALA group-control) or 30g of L-glutamine (GLN group) daily for a period of fourteen days. We analyzed the gut microbiota composition with new generation sequencing techniques and bioinformatics analysis.
Results
After fourteen days of supplementation, subjects in the GLN group exhibited statistically significant differences in the Firmicutes and Actinobacteria phyla compared with those in the ALA group. The F/B (Firmicutes/Bacteroidetes) ratio, a good biomarker for obesity, decreased in the GLN group from 0.85 to 0.57, while it increased from 0.91 to 1.12 in the ALA group. At the genus level, Dialister, Dorea, Pseudobutyrivibrio and Veillonella, belonging to the Firmicutes phylum, had statistically significant reduction.
Conclusion
Oral supplementation with L-glutamine, for a short time, altered the composition of the gut microbiota in overweight and obese humans reducing the Firmicutes/Bacteroidetes ratio, which resembled weight loss programs already seen in the literature.
