TABLE 4.
Glucose- or food-stimulated GLP-1 secretion after short-, mid-, and long-term dietary 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/iAUC (pmol/L ∗ min) | Results | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 30 | 60 | 90 | 120 | 150 | 180 | |||||||||
| Glucose-stimulated GLP-1 secretion (OGTT) before and after dietary intervention | |||||||||||||||
| Otten et al. 2019 [72] n = 70 RCT |
RIA1 | 2-y intervention: Paleo diet (PD) Healthy Nordic Diet (ND) (slight energy reduction) NGT (BMI: 32.3 kg/m2) females |
ND# | 0 mo | 10 | 18 | 20 | 18 | 17 | 60 | 10 | 120 min: AUC: 2424 iAUC: 1084 |
- ↑ AUC, iAUC in PD and ND compared with baseline - ↑ fasting values in ND compared with baseline |
||
| 6 mo | 10 | 21 | 21 | 19 | 19 | 30 60 |
11 | 120 min: AUC: 2769 iAUC: 1449 |
|||||||
| 24 mo | 12 | 27 | 26 | 24 | 22 | 30 | 15 | 120 min: AUC: 2826 iAUC: 1572 |
|||||||
| PD# | 0 mo | 11 | 23 | 21 | 22 | 20 | 30 | 12 | 120 min: AUC: 2113 iAUC: 933 |
||||||
| 6 mo | 11 | 25 | 26 | 25 | 24 | 60 | 15 | 120 min: AUC: 2287 iAUC: 1036 |
|||||||
| 24 mo | 11 | 26 | 26 | 26 | 24 | 30 60 90 |
15 | 120 min: AUC: 2907 iAUC: 1488 |
|||||||
| Stentz et al. 2021 [74] n = 24 RCT |
Human Metabolic Hormone Magnetic Bead Panel (Merck)2 |
6-mo intervention: Calorie restricted diets (-500 kcal) High-Protein Diet (HP, 40% CH, 30% F, 30% P) High-Carbohydrate Diet (HC, 55% CH, 30% F, 15% P) OW-IGT (BMI: 39.0 kg/m2) |
HP | 0 mo | 13 | 68 | 44 | 30 | 27 | 30 | 55 | n.a. |
↑ AUC in HP compared with HC |
||
| 6 mo | 17 | 85 | 56 | 38 | 29 | 30 | 68 | ||||||||
| HC |
0 mo | 15 | 67 | 41 | 29 | 24 | 30 | 52 | |||||||
| 6 mo |
15 |
67 |
48 |
29 |
24 |
30 |
52 |
||||||||
| Food-stimulated GLP-1 secretion (test meal) before and after dietary intervention | |||||||||||||||
| Samkani et al. 2018 [78] n = 16 RCT cross-over |
RIA1 | 2-d intervention: High-CH (HC, 54% CH, 30% F, 16% P) CH-reduced high-protein (CRHP, 31% CH, 40% F, 29% P) Breakfast test meal on day 2 T2DM (BMI:: 30 kg/m2) |
HC Day 2 |
11 | 24 | 30 | 26 | 26 | 28 | 25 | 60 | 19 | n.a. | - ↑ postprandial value (120 min) in CRHP compared with HC - ↔ netAUC |
|
| CRHP Day 2 |
11 | 18 | 28 | 30 | 34 | 32 | 28 | 120 | 23 | ||||||
| Samkani et al. 2018 [77] n = 14 RCT cross-over |
RIA1 | 2-d intervention: HC (54% CH, 30% F, 16% P) CRHP (31% CH, 40% F 29% P) Breakfast test meal on day 2 NW to OW (BMI:: 32 kg/m2) |
HC Day 2 |
0 | 11 | 12 | 12 | 16 | 14 | 13 | 120 | 16 | n.a. | ↑ postprandial/ peak, netAUC values in CRHP compared with HC | |
| CRHP Day 2 |
0 | 9 | 14 | 15 | 20 | 20 | 18 | 120 150 | 20 | ||||||
| Fuglsang-Nielsen et al. 2021 [76] n = 73 RCT |
RIA1 | 12 wks intervention: Whey Protein (WP, 60 g/d) or Maltodextrin (MD, 60 g/d) combined with High-Fiber (HF, 30 g/d) or Low-Fiber diet (LF, 10 g/d) High-fat mixed meal test at baseline and endline (360 min) OW (BMI:: 29.4 kg/m2) |
WP-HF | 0 wk | 19.3# | 360 min: iAUC: 6143# |
↔ fasting values, iAUC | ||||||||
| 12 wks | 20.2# | 360 min: iAUC: 3791# |
|||||||||||||
| WP-LF | 0 wk | 21.5# | 360 min: iAUC: 4174# |
||||||||||||
| 12 wks | 19.6# | 360 min: iAUC: 4264# |
|||||||||||||
| MD-HF | 0 wk | 21.2# | 360 min: iAUC: 3896# |
||||||||||||
| 12 wks | 21.1# | 360 min: iAUC: 4676# |
|||||||||||||
| MD-LF | 0 wk | 21# | 360 min: iAUC: 3471# |
||||||||||||
| 12 wks | 20.7# | 360 min: iAUC: 3062# |
|||||||||||||
| Oliveira et al. 2022 [75] n = 43 RCT cross-over |
V-PLEX (Meso Scale)3 | 32-h intervention: IG: High-protein total diet replacement (35% CH, 25% F, 40% P) CG: (55% CH, 30% F, 15% P) Lunch test meal on day 1 NW (BMI:: 22.0 kg/m2) |
IG# | Day 1 | 1.6 | 4.2 | 120 | 2.6 | n.a. | ↑ postprandial values in IG compared with CG on day 1 ↑ fasting values in CG compared with IG on day 2 |
|||||
| Day 2 | 1.2 | ||||||||||||||
| CG# | Day 1 | 1.6 | 2.6 | 120 | 1 | ||||||||||
| Day 2 | 1.5 | ||||||||||||||
| Day 2 | 6.7# | 12 | 10 | 9 | 8 | 10 | 9 | 30 | 5.3 | 180 min: AUC: 440 |
|||||
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 or iAUC 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 5 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; CRHP, carbohydrate-reduced-high-protein; CV, coefficient of variation; ELISA, enzyme-linked immunosorbent assay; F, fat; GLP-1, glucagon-like peptide 1; HC, high-carbohydrate; HF, high fiber; HP, high protein; iAUC, incremental area under the curve; iFG, impaired fasting glucose; IG, intervention group; IGT, impaired glucose tolerance; LF, low fiber; LOD, limit of detection; MD, maltodextrin; min, minutes; n.a., not available; ND, healthy nordic diet; NGT, normal glucose tolerance; NW, normal weight, OW, overweight; P, protein; PD, paleo diet; RCT, randomized controlled trial; RIA, radioimmunoassay; RPCT, randomized placebo-controlled trial; RT, randomized trial; TTP, time-to-peak; T2DM, type 2 diabetes mellitus; WP, whey protein.
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);
Human Metabolic Hormone Magnetic Bead Panel MILLIPLEX MAP Kits (Cat. # HMHEMAG-34K, Merck), sensitivity: 7.3 pg/mL, intra-assay CV: < 10%, inter-assay CV: < 15%.
Electro-chemiluminescence V-PLEX (Meso Scale Discovery), specificity: 0.017 pM.