A comprehensive insight into the effect of glutamine supplementation on metabolic variables in diabetes mellitus: a systematic review

What this study found

Glutamine supplementation can improve glycemic control and incretin hormone levels in diabetes mellitus. Fasting blood glucose and postprandial glucose decreased in several studies; GLP-1 levels increased in multiple studies; insulin production increased in several studies. HbA1c results were inconclusive; lipid outcomes were inconsistent; weight changes and oxidative stress/inflammation showed promise but require more robust trials. Overall, glutamine may improve glycemic control and incretin levels, but definitive efficacy and long-term safety require well-designed clinical trials.

Study & population

Systematic review of clinical trials and animal studies evaluating glutamine effects on metabolic variables in diabetes mellitus; English-language; up to April 2020; included human studies (predominantly type 2 diabetes, with some type 1 diabetes in adolescents) and animal studies; study designs included randomized controlled trials; quality assessed with…

Intervention

Oral L-glutamine; typical dosage ranged from 15–30 g/day; duration generally 4–6 weeks; taken as a drink after being dissolved in water; some regimens included co-administration with sitagliptin or placebo.

Key limitation

Small sample sizes and short durations in many human studies; heterogeneity in populations, dosing regimens, and outcomes; reliance on surrogate endpoints; mixed design including animal studies; inconsistent lipid and HbA1c results; potential bias due to study quality and limited long-term data.

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