Table 1.
Summary characteristics of included studies (n = 12).
| Study, Country, Year |
Study Design |
Sample Size |
Participants | Mean Age (Years) | Type of Diet | Intervention Duration |
Genomic Methods |
|---|---|---|---|---|---|---|---|
| Peltonen et al. [14] Finland 1994 |
RCT | 53 | Rheumatoid arthritis |
VD = 53 Omnivorous diet = 56 |
Vegan and LV vs. omnivorous diet | 13 months | Gas–liquid chromatography |
| Peltonen et al. [15] Finland 1997 |
RCT | 36 | Rheumatoid arthritis |
VD: 49.1 Omnivorous diet = 51.6 |
Vegan vs. omnivorous diet | 1 month | Gas–liquid chromatography |
| Kim et al. [17] Korea 2013 |
Pre–post intervention |
6 | Obese individuals with T2DM and/or HT | 61.6 | Vegan | 1 month | 16s-RNA sequencing and gas chromatography |
| David et al. [16] USA 2014 |
Non-RCT | 10 | Healthy | 21–33 | Plant-based vs. animal-based diet | 5 days | 16s-RNA sequencing and gas chromatography |
| Zhang et al. [18] Sweden 2018 |
RCT | 29 | Healthy | NR | OLV vs. omnivorous diet | 12 weeks | 16s-RNA sequencing |
| Pagliai et al. [19] Italy 2019 |
RCT | 23 | Overweight adults with low-to-moderate risk for CVD | 58.6 ± 9.8 | OLV vs. MD | 12 weeks | 16s-RNA sequencing and gas chromatography |
| Kahleova et al. [20] USA 2020 |
RCT | 168 | Overweight | Intervention = 52.9 ± 11.7. Control = 57.5 ± 10.2 | Low-fat vegan diet vs. omnivorous diet | 16 weeks | 16s-RNA sequencing |
| Djekic et al. [21] Sweden 2020 |
RCT | 31 | Adults with history of IHD |
67 | OLV vs. isocaloric VD | 4 weeks | 16s-RNA sequencing and gas chromatography |
| Ahrens et al. [22] USA 2021 |
Pre–post intervention |
73 | Adults with HT | 46.89 ± 12.38 | Plant-based diet | 1 week | 16s-RNA sequencing |
| Kohnert et al. [23] Germany 2021 |
RCT | 53 | Healthy | VD = 33.2 ± 11.2 MD = 29.9 ± 9.5 |
Free choice vegan diet vs. free choice meat-rich diet | 4 weeks | 16s-RNA sequencing |
| Toribio-Mateas et al. [24] UK 2021 |
RCT | 39 | Healthy | 37.5 ± 8.9 | Plant-based meat vs. omnivorous diet | 4 weeks | 16s-RNA sequencing |
| Kahleova et al. [25] USA 2021 |
RCT | 62 | Overweight | 30–76 | Vegan diet vs. omnivorous diet |
16 weeks | 16s-RNA sequencing |
RCT, randomized controlled trial; NR, not reported; T2DM, type 2 diabetes mellitus; HT, hypertension; CVD, cardiovascular disease; IHD, ischemic heart disease; OLV, ovo-lacto vegetarian diet; LV, lacto-vegetarian diet; VD, vegetarian diet; MD, Mediterranean diet.