TABLE 6.
Glucose- or food-stimulated GLP-1 secretion after pro-, pre-, and synbiotic interventions
| Author, (y), n | GLP-1 assay | Intervention Participant characteristics |
GLP-1 values (pmol/L) at time points (min) |
TTP (min) | Δ Peak (pmol/L) | GLP-1 AUC (pmol/L∗min) | Results | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 20 | 30 | 45 | 60 | 90 | 120 | 180 | |||||||||||
| Glucose-stimulated GLP-1 secretion (OGTT) before and after interventionrowhead | ||||||||||||||||||
| Simon et al. 2015 [43] n = 21 RPCT |
RIA1 |
4 wks IG: Probiotics (1010 b.i.d. L. reuteri SD5865) CG: Placebo NW-NGT (n = 11, BMI:: 23.6 kg/m2) OW-NGT (n = 10, BMI:: 35.5 kg/m2) |
IG | NW baseline# | 6 | 17 | 24 | 21 | 22 | 22 | 13 | 30 | 18 | n.a. |
- ↑postprandial values, AUC in IG compared with baseline and CG - ↑ΔAUC in IG compared with CG |
|||
| NW 4 wks# | 9 | 34 | 37 | 37 | 29 | 5 | 16 | 30 60 |
28 | |||||||||
| OW baseline# | 6 | 16 | 12 | 15 | 14 | 11 | 6 | 20 | 10 | |||||||||
| OW 4 wks# | 6 | 17 | 19 | 20 | 15 | 18 | 11 | 60 | 14 | |||||||||
| CG |
NW baseline# | 7 | 18 | 20 | 24 | 21 | 23 | 16 | 60 | 17 | ||||||||
| NW 4 wks# | 8 | 17 | 21 | 20 | 20 | 17 | 12 | 30 | 13 | |||||||||
| OW baseline# | 8 | 19 | 18 | 15 | 15 | 14 | 10 | 20 | 11 | |||||||||
| OW 4 wks# |
5 |
14 |
14 |
13 |
14 |
13 |
8 |
20 30 60 |
9 |
|||||||||
| Food-stimulated GLP-1 secretion (test meal) before and after interventionrowhead | ||||||||||||||||||
| Roshanravan et al. 2017 [23] n = 60 RPCT |
ELISA (ZellBio GmbH, Berlin, Germany)2 | 45 d Prebiotic supplements A) sodium butyrate B) inulin C) sodium butyrate + inulin D) placebo Breakfast test meal T2DM (BMI:: 33.3 kg/m2) |
A | Baseline | 27 | n.a. | n.a. | n.a. | ↑ postprandial values in A + C compared with D | |||||||||
| 45 d | 32 | |||||||||||||||||
| B | Baseline | 21 | ||||||||||||||||
| 45 d | 26 | |||||||||||||||||
| C | Baseline | 29 | ||||||||||||||||
| 45 d | 32 | |||||||||||||||||
| D | Baseline | 22 | ||||||||||||||||
| 45 d | 21 | |||||||||||||||||
| Müller et al. 2020 [81] n = 48 RPCT |
RIA1 | 12 wks IG: Prebiotics (15 g/d Arabinoxylan-Oligosaccharide) CG: Placebo Breakfast test meal: 2 slices of white bread, fried egg, chocolate milk (412 kcal, 52% CH, 27% F, 19% P) NGT (BMI:: 24.5 kg/m2) |
IG | Baseline | 24 | 32 | 31 | 31 | 31 | 29 | 30 | 8 | 90 min: 1767 | ↓ early AUC (0-90 min) in IG compared with CG | ||||
| 12 wks | 23 | 24 | 26 | 31 | 30 | 25 | 90 | 8 | 90 min: 1487 | |||||||||
| CG | Baseline | 23 | 31 | 32 | 30 | 31 | 28 | 60 | 9 | 90 min: 1729 | ||||||||
| 12 wks | 23 | 32 | 29 | 33 | 28 | 26 | 90 | 10 | 90 min: 1754 | |||||||||
| Birkeland et al. 2021 [82] n = 25 RPCT cross-over |
RIA1 | 6 wks IG: Prebiotics (16 g/d inulin-type fructans) CG: Placebo Mixed meal test (Fresubin Drink vanilla + Jucy Drink apple, 550 kcal, 78.5 g CH, 15.6 g F, 24 g P) T2DM (BMI:: 29.1 kg/m2) |
IG | Baseline | 28 | 50 | 47 | 40 | 42 | 39 | 37 | 30 | 22 | 180 min: 7180# | - ↔ AUC - ↓ decrease in postprandial excursion in IG compared with CG |
|||
| 6 wks | 27 | 44 | 45 | 40 | 40 | 36 | 36 | 45 | 18 | 180 min: 6979# | ||||||||
| CG | Baseline | 27 | 47 | 47 | 40 | 41 | 37 | 36 | 30 45 | 20 | 180 min: 6998# | |||||||
| 6 wks | 28 | 58 | 54 | 45 | 45 | 39 | 36 | 30 | 30 | 180 min: 7596# | ||||||||
GLP-1 concentrations for selected time points of blood sampling, time-to-peak as well as peak (peak concentration – fasting concentration), and —if available—AUC values are listed. Under “results” only significant results are listed. Time point 0 describes fasting concentrations, and time points >0 are reporting postprandial concentrations. Under “results” only significant results are listed.
#original data, ↑ higher GLP-1 secretion in comparison to referred groups, ↓ lower GLP-1 secretion in comparison to referred groups, ↔ no differences of GLP-1 secretion between groups. Supplemental Table 6 shows GLP-1 values for all measured time points. Details on GLP-1 assays as stated in the publications or according to manufacturer instructions:
Abbreviations: AUC, area under the curve; CH, carbohydrates; CG, control group; CV, coefficient of variation; ELISA, enzyme-linked immunosorbent assay; F, fat; GLP-1, glucagon-like peptide 1; iAUC, incremental area under the curve; IG, intervention group; LOD, limit of detection; min, minutes; n.a., not available; NGT, normal glucose tolerance; NW, normal weight, P, protein; RIA, radioimmunoassay; RPCT, randomized placebo-controlled trial; TTP, time-to-peak; T2DM, type 2 diabetes mellitus.
RIA [standardized assay (41)], polyclonal antiserum no. 89390, LOD: 1 pM, intra-assay CV: 6%, specificity: 100% for GLP-1 (7–36) 89% for GLP-1 (9–36);
ELISA (ZellBio GmbH, Berlin, Germany), sensitivity: 8.2 pg/mL.