Oral supplementation with L-glutamine alters gut microbiota of obese and overweight adults: A pilot study.
OBJECTIVE
The aim of this study was to determine whether oral supplementation with L-glutamine (GLN) modifies the gut microbiota composition in overweight and obese adults.


METHODS
Thirty-three overweight and obese adults, ages between 23 and 59 y and body mass index between 25.03 and 47.12 kg/m(2), were randomly assigned to receive either oral supplementation with 30 g of L-alanine (ALA group control) or 30 g of GLN (GLN group) daily for 14 d. We analyzed the gut microbiota composition with new-generation sequencing techniques and bioinformatics analysis.


RESULTS
After 14 d of supplementation, adults in the GLN group exhibited statistically significant differences in the Firmicutes and Actinobacteria phyla compared with those in the ALA group. The ratio of Firmicutes to Bacteroidetes, a good biomarker for obesity, decreased in the GLN group from 0.85 to 0.57, whereas 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.


CONCLUSIONS
Oral supplementation with GLN, for a short time, altered the composition of the gut microbiota in overweight and obese humans reducing the Firmicutes to Bacteroidetes ratio, which resembled weight loss programs already seen in the literature.
School of Applied Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Alessandra Zanin Zambom
AZ
de Souza
Department of Statistics, State University of Campinas, Campinas, São Paulo, Brazil.
Adriano Zanin
AZ
Zambom
School of Applied Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Kahlile Youssef
KY
Abboud
School of Applied Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Sabrina Karen
SK
Reis
School of Applied Sciences, State University of Campinas, Campinas, São Paulo, Brazil.
Fabiana
F
Tannihão
Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, Brazil.
Dioze
D
Guadagnini
Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, Brazil.
Mario J A
MJ
Saad
School of Applied Sciences, State University of Campinas, Campinas, São Paulo, Brazil; Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, Brazil. Electronic address: pprada@fcm.unicamp.br.
Patricia Oliveira
PO
Prada
D000284:Administration, Oral; D000328:Adult; D001419:Bacteria / Q000187:drug effects* / Q000254:growth & development; D041963:Bacteroidetes / Q000187:drug effects / Q000254:growth & development; D015992:Body Mass Index; D019587:Dietary Supplements; D005260:Female; D000068536:Bacillota / Q000187:drug effects / Q000254:growth & development; D000069196:Gastrointestinal Microbiome / Q000187:drug effects*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D005973:Glutamine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000382:microbiology*; D050177:Overweight; D010865:Pilot Projects; D055815:Young Adult
D005973:Glutamine
16S rRNA; Firmicutes; Glutamine; Humans; Microbiota; Obese; Overweight