Table 3.
Characteristics of human studies that reported the effects of glutamine on metabolic variables in diabetes mellitus
| Author, place, year | Type of study | Subjects | Sample size | Age (years) | Daily dose | Duration | Main outcomes |
|---|---|---|---|---|---|---|---|
| Greenfield et al., UK, 2009 [33] | RCT | T2DM | 24 | 30–40 | 75 g glucose in 300 ml of water and 30 g glutamine in 300 ml of water | 3 separate occasions over a period of < 1 month |
Significant increase GLP-1, insulin production, glucagon, GIP levels |
| Samocha-Bonet et al., Australia, 2011 [14] | Crossovr study | T2DM | 15 | 40–70 |
30 g L-glutamine (Gln-30), 15 g L-glutamine (Gln-15),100 mg sitagliptin (SIT) and 100 mg SIT plus Gln-15 (SIT + Gln-15) |
1–2 weeks |
Significant reduce postprandial glucose response Significant increase postprandial insulin response, C-peptide, postprandial glucagon concentration total GLP-1 |
| Lomivorotov et al., russia, 2012 [31] | RCT | T1DM | 64 |
Intervention: (60 ± 7) |
0.4 g/kg/day of 20% solution of N(2)-L-alanyl-L-glutamine | 4 weeks |
No significant change Insulin resistance, insulin sensitivity, β-cell function, fasting blood glucose, TG |
| Chang et al., Australia, 2013 [29] | RCT | T2DM | 20 |
Healthy Men: (29.5 ± 3.8) T2DM Patients: (68 ± 1.1) |
7.5 or 15 g glutamine or 350 mL of 0.9% saline |
0–30 min |
Significant increase GLP-1, GIP, insulin and glucagon levels Insignificant Fasting blood glucose |
| Mansour et al., Iran, 2014 [28] | RCT | T2DM | 66 | 18–65 | 30 g/d glutamine | 6 weeks |
Significant reduce Trunk fat, Total fat, Total fat free mass, HbA1c, body fat mass, percent body fat, WC, appendicular fat Fasting blood glucose Significant increase Trunk fat-free mass, Trunk fat mass, Appendicular fat free mass, Total fat mass, Appendicular fat, Plasma glutamine concentration, fat-free mass Insignificant Body weight, BMI, Fasting insulin, HOMA-IR, QUICKI, TG, Cholesterol, HDL-C, LDL-C, CRP |
| Samocha-Bonet et al., Australia, 2014 [26] | Crossover study | T2DM | 13 | 40–70 | glutamine (15 gbd) + sitagliptin (100 mg/d) | 4 weeks |
Significant reduce postprandial glucose Insignificant HbA1c, Fasting plasma glucose Significant Increase GLP-1, |
| Takeuti et al., Brazil, 2014 [30] | RCT | T2DM | 11 | 21–60 | 9 g palm oil and 30 g glutamine diluted in 200 ml of water | 2 separate days |
Significant reduce in palm oil group BG and PYY “in 2 h after the stimulus”, GLP-1 “in 1 h after the stimulus” Insignificant in palm oil group BG and PYY “in 1 h after the stimulus”, GLP-1 “in 2 h after the stimulus” Significant reduce in glutamine group BG “in 2 h after the stimulus” Insignificant in glutamine group BG “in 1 h after the stimulus”, PYY & GLP-1 “in 1&2 h after the stimulus” |
| Samocha-Bonet et al., Australia, 2015 [27] | Randomized crossover study | T2DM | 10 | 40–70 | L-glutamine (25 g), protein (25 g) or water | 1–2 weeks |
Significant Reduce postprandial glycaemia Significant increase in protein group first-phase insulin, total GLP-1, Second-phase insulin response was significantly augmented by protein Significant increase in glutamine group Total GLP-1 |
| Meek, et al. UK, 2016 [34] | Crossover study | Healthy and T2DM | 37 | 22–30 |
3–6 g Ileal release glutamine |
4 h |
Insignificant change GLP-1, insulin, glucose tolerance |
| Torres-Santiago, USA, 2017 [32] | Crossover study | T1DM | 13 | 8 boys and 5 girls; mean age 15.9 ± 1.6 years | Drink containing 0.25 mg/kg glutamine | 4 weeks |
Significant reduce Fasting Blood glucose Insignificant change Insulin sensitivity, plasma GLP-1, basFal plasma free insulin concentration |
GLP-1 Glucagon-like peptide-1, GIP Gastric inhibitory polypeptide, BG blood sugar, PYY peptide YY, FBS Fasting Blood Sugar, TG Triglyceride, TC Total Cholesterol, HDL high density lipoprotein, LDL low-density lipoprotein, WC waist circumference, BMI body mass index, HOMA-IR Homeostatic Model Assessment-Insulin Resistance Index, TG;Triglycerides, QUICKI Quantitative Insulin Sensitivity Check Index