18) Nutrients. 2021 Mar 22;13(3):1025.

L-Glutamine Supplementation Enhances Strength and Power of Knee Muscles and Improves Glycemia Control and Plasma Redox Balance in Exercising Elderly Women

Gislene R Amirato 1, Juliana O Borges 1, Daniella L Marques 1, Juliana M B Santos 2, Carlos A F Santos 3, Marilia S Andrade 4, Guilherme E Furtado 5, Marcelo Rossi 6, Lais N Luis 1, Raquel F Zambonatto 1, Eliane B da Silva 1, Sarah O Poma 1, Mariana M de Almeida 1, Renato L Pelaquim 1, Laiane C Dos Santos-Oliveira 1, Vinicius L Sousa Diniz 1, Maria E P Passos 1, Adriana C Levada-Pires 1, Renata Gorjão 1, Marcelo P Barros 1, André L L Bachi 6 7, Tania C Pithon-Curi 1

Abstract

We investigated the effects of oral L-glutamine (Gln) supplementation, associated or not with physical exercises, in control of glycemia, oxidative stress, and strength/power of knee muscles in elderly women. Physically active (n = 21) and sedentary (n = 23) elderly women aged 60 to 80 years were enrolled in the study. Plasma levels of D-fructosamine, insulin, reduced (GSH) and oxidized (GSSG) glutathione, iron, uric acid, and thiobarbituric acid-reactive substances (TBARs) (lipoperoxidation product), as well as knee extensor/flexor muscle torque peak and average power (isokinetic test), were assessed pre- and post-supplementation with Gln or placebo (30 days). Higher plasma D-fructosamine, insulin, and iron levels, and lower strength/power of knee muscles were found pre-supplementation in the NPE group than in the PE group. Post-supplementation, Gln subgroups showed higher levels of GSH, GSSG, and torque peak, besides lower D-fructosamine than pre-supplementation values. Higher muscle average power and plasma uric acid levels were reported in the PE + Gln group, whereas lower insulin levels were found in the NPE + Gln than pre-supplementation values. TBARs levels were diminished post-supplementation in all groups. Gln supplementation, mainly when associated with physical exercises, improves strength and power of knee muscles and glycemia control, besides boosting plasma antioxidant capacity of elderly women.