L-glutamine supplementation improves upper airways immune response in sedentary and physically active elderly

L-glutamine (LG) supplementation boost the immune system and benefit elderly, who present immunosenescence. However, no study has evaluated its effects on the humoral immune response of upper airways of elderly. Thus, this study evaluated the effects of LG in elderly sedentary (Sed) and physically active (CET=combined-exercise training: aerobic+resistance exercise), supplemented or not with LG, on pulmonary function and the levels of IL-6, IL-10 and IL-6/IL-10 ratio in the nasal lavage fluid (NLF) and in the saliva, as biomarkers of humoral immune response of upper airways. Four experimental groups were tested: Sed+Pl (n=15), Sed+LG (n=19), CET+Pl (n=26) and CET+LG (n=23), after 30 days of supplementation with L-glutamine (LG=0.3g/kg/day + 10g/day maltodextrin) or placebo (Pl=10g/day maltodextrin). No differences in forced vital capacity and in forced expiratory volume in the first second was observed among all groups. The levels of salivary IL-6 of Sed+Pl before supplementation and Sed-PI and Sed-LG after supplementation were lower, as well as the IL-10 levels of Sed groups (Sed and Sed+LG) before and after supplementation compared to CET groups. In a different way, it was observed higher levels of IL-6 in the NLF of Sed-Pl before supplementation and Sed-Pl and Sed-LG after supplementation compared to CET groups. The differences in the NLF IL-10 levels were like observed in saliva. On the other hand, the IL-6/IL-10 ratio were lower in the CET-Pl before and after supplementation and in the CET-LG after supplementation. In conclusion, LG supplementation improves the humoral immune response of upper airways of sedentary and physically active elderly.