Table 6.
Randomized clinical trials pointing to the role of SCFAs in the maintenance of glucose homeostasis, in metabolic syndrome, and in type 2 diabetes.
| Author Year |
Study Groups | Number (M/F) |
BMI Kg/m2 |
Study Design | Duration | Intervention | Major Findings |
|---|---|---|---|---|---|---|---|
| Vitale et al., 2021 [115] | At least one criterion of MetS (overweight/obesity) |
29 (14/15) |
25–35 | Parallel | 8 weeks | Mediterranean diet consisting of fiber 19.3 g/1000 kcal compared with control diet consisting of fiber 8.1 g/1000 kcal) |
↑ Intestinimonas butyriciproducens ↑ Akkermansia muciniphila ↑ Plasma butyric acid ↓ Postprandial glucose ↓ Postprandial insulin ↑ Oral glucose insulin sensitivity |
| Zhao et al., 2018 [101] | Type 2 DM | 43 | 25–35 | Parallel | 12 weeks | High-fiber diet consisting of fiber 37.1 g compared with control diet consisting of fiber 16.1 g | ↑ Fecal butyrate ↓ HbA1c ↓ Fasting glucose |
| Haro et al., 2016 [116] | MetS (insulin sensitivity/obesity) |
20 (20/0) |
30–40 | Parallel | 1 year | Mediterranean diet consisting of fiber: 12.9 ± 0.2 g/Kcal mainly from vegetables compared with high-fiber diet consisting of fiber: 14.1 ± 0.2 g/1000 kcal, mainly form wholegrains | ↑ Roseburia ↓ Prevotella ↑ Insulin sensitivity index High-fib diet ↓ Roseburia ↑ Prevotella |
| Hald et al., 2016 [117] | MetS | 19 | 25.9–41 | Crossover | 4 weeks | Diet enriched with Arabinoxylan and Resistant starch consisting of fiber 64 g compared with Western diet consisting of fiber 17.6 g | ↑ Bifidobacteria ↑ Fecal SCFAs ↑ Fecal butyrate |
| Vetrani et al., 2016 [118] | MetS (overweight/obesity and type 2 diabetes) |
40 (16/24) |
25–35 | Parallel | 12 weeks | Wholegrain diet consisting of total fiber 40 g with fiber from cereal 28.9 g, compared with refined cereal diet consisting of total fiber 22.1 g with fiber from cereal 11.8 g | ↑ Plasma propionate ↓ Postprandial insulin |
| Kovatcheva-Datchary et al., 2015 [111] | Healthy individuals | 39 (6/33) |
18–28 | Parallel | 3 days | Barley kernel-based bread consisting of fiber 37.6 g compared with white wheat bread consisting of fiber 9.1 g | ↑ Prevotella:Bacteroides ↓ Postprandial glucose |
| Nilsson et al., 2015 [112] | Healthy individuals | 20 (3/17) |
18–28 | Crossover | 3 days | Barley kernel-based bread consisting of fiber 37.6 g compared with white wheat bread consisting of fiber 9.1 g | ↑ Plasma SCFAs ↓ Glucose ↓ Insulin |
| David et al., 2014 [93] | Healthy individuals | 10 (5/5) |
19–32 | Crossover | 4 days | Plant-based diet consisting of fiber 26 g/1000 kcal compared with Western diet consisting of fiber 9.3 g/1000 kcal | ↑ Prevotella ↑ Roseburia ↑ Fecal butyrate Western diet ↓ Prevotella ↑ Bacteroides |
| Freeland et al., 2010 [114] | Hyperinsulinaemic individuals | 28 | 24–27 | Parallel | 1 year | High-wheat fiber cereal consisting of 24 g fiber/day compared with low-fiber cereal | ↑ Acetate and butyrate concentrations ↑ Plasma GLP-1 |
Abbreviations: ↓—significant decrease; ↑—significant increase; BMI—body mass index; HbA1c—glycated hemoglobin; GLP-1—glucagon-like peptide-1; MetS—metabolic syndrome; SCFAs—short chain fatty acids.