| Kohnert et al. (2021) | Randomized, controlled trial | Meat-rich diet; >150 g of meat/d Strict vegan diet | 4 wk | 53 Healthy adults 18–60 yr | In meat-rich groupNo change in alpha- or beta-diversity Coprococcus ↓ Roseburia ↑ Faecalibacterium ↑ Blautia ↑ |
| Russell et al. (2011) | Randomized, crossover trial | Maintenance diet (M); 13% protein and 50% carbohydratesHigh-protein and moderate-carbohydrate diet (HPMC); 28% protein and 35% carbohydrateHigh-protein and low-carbohydrate (HPLC); 29% protein and 5% carbohydrate | 4 wk | 17 Healthy males 21–74 yr Body mass index (BMI) 27.88–48.48 | In HPLC groupRoseburia/Eubacterium rectale ↓ Bacteroides spp. ↓ |
| Foerster et al. (2014) | Randomized, crossover trial | Low-meat high-fiber period; whole grain products, 40 g of fiber/dHigh-meat low-fiber period; 200 g of red meat/d | 3 wk | 20 Healthy adults 20–60 yr | In high-meat low-fiber period Clostridium sp. ↓ |
| Hentges et al. (1977) | Crossover trial | High-beef diet; 380 g of beef/dMeatless diet; 360 g milk; 150 g egg; 145 g cheese; 100 g peas | 4 wk | 10 Healthy males | In high-beef dietGenus Bacteroides ↑Species Bacteroides fragilis ↑ Bifidobacterium adolescentis ↓ |
| Zhao et al. (2019b) | Crossover, controlled trial | Beef-based diet Chicken-based diet | 2 wk | 45 Healthy males 18–27 yr | In beef-based dietLachnospira ↓ Lachnospiraceae NK4A136 group ↓ Ruminococcus 2 ↓ |
| Dhakal et al. (2022) | Randomized, crossover, controlled trial | Pork group; 156 g pork/d Chicken group; 156 g chicken/d | 10 d | 50 Healthy older adults 66.44±7.44 yr BMI 29.8±5.59 | In both groupsNo change in alpha- or beta-diversityPhylum Bacteriodetes ↓Family Bacteriodaceae ↓ Christencellaceae ↑In pork groupRuminiclostridium 5 ↑In chicken groupRoseburia ↓ |
| Shi et al. (2021) | Cross-sectional study | Not applicable (NA) | NA | 40 Healthy males 18–30 yr; chicken-eaters (n=20) and pork-eaters (n=20) | In pork-eater groupChao and Shannon index ↓Phylum Firmicutes ↑ Bacteroidetes ↓Genus Clostridiales, Bacteroides, Firmicutes, Lachnospiraceae, Faecalibacterium, Roseburia, Ruminococcus 2, and Blautia ↑In chicken-eater groupPhylum Firmicutes ↓ Bacteroidetes ↑Genus Prevotellaceae, Prevotella 9, Bacteroidales, Dialister, Prevotella 2, Ruminococcaceae UCG 002, Lactobacillus, and Olsenella ↑ |
| Sinha et al. (2021) | Dietary intervention (participants were blinded to which group they were assigned) | First phase (2 wk): conventional processed meats (Diet A)Second phase (2 wk): poultry (i.e., chicken and turkey) (Diet B)Third phase (2 wk): Group 1) conventional processed meat supplemented with natural phytochemical compounds (Diet C)Group 2) low-nitrite processed meat supplemented with phytochemical compounds (Diet D)Final phase (1 wk): nitrate-enriched water with diet A, B, C, or D | 7 wk | 63 Healthy volunteers (participants of each sex were randomly assigned to one of the two experimental groups)(ages 18–70, in good health, with a BMI between 18 and 25 kg/m2) | NA |
| Gao et al. (2021) | Randomized controlled-feeding trial | Control group: restricted from fried meat intake (n=58)Fried meat group: fried meat four times per week (n=59) | 4 wk | 117 Participants, (18–35 yr old, BMI>24 kg/m2, and consumption of fried food more than one time per wk) | Family Lachnospiraceae ↓Genus Flavonifractor ↓ Dialister ↑ Dorea ↑ Veillonella ↑ |
| Thøgersen et al. (2018) | Chow,Conventional frankfurter sausage | Inulin-enriched frankfurter sausage | 4 wk | 30 Healthy Sprague-Dawley rats | Phylum Actinobacteria ↑Family unclassified Lachnospiraceae ↑ Erysipelotrichaceae ↑Genus Bifidobacterium ↑Species Bacteroides uniformis ↑ |
| Thøgersen et al. (2020) | Control sausage | Sausage+inulin and calcium Sausage+inulin Sausage+calcium | 4 wk | 48 Healthy Sprague-Dawley rats | Phylum Firmicutes ↑ (Sausage+calcium, Sausage+inulin and calcium) Bacteroidetes ↓ (Sausage+calcium, Sausage+inulin and calcium) Proteobacteria, Cyanobacteria ↓ (Sausage+inulin and calcium) Deferribacteres ↑ (Sausage+calcium) Actinobacteria ↑ (Sausage+inulin and calcium)Genus Muribaculaceae, uncultivated Ruminococcaceae ↑ (Sausage+Inulin) Clostridium 6, Staphylococcus, uncultivated Ruminococcaceae (PAC000661) ↑ (Sausage+calcium) uncultivated genus (PAC002482), Parabacteroides, Alistipes, Clostridium, unclassified Peptostreptococcaceae ↓ (Sausage+calcium)Bifidobacterium, Staphylococcus, Blautia, uncultivated Ruminococcaceae (PAC000661), uncultivated Erysipelotrichaceae (CCMM), Faecalibaculum ↑ (Sausage+inulin and calcium)Bacteroides, Parabacteroides, Alistipes, Clostridium, Dorea, uncultivated Bacteroidetes (PAC002482), Muribaculaceae (PAC001472), Lachnospiraceae (KE159600), unclassified Firmicutes ↓ (Sausage+inulin and calcium)Lactobacillus ↑ (q=0.63; Sausage+calcium, Sausage+inulin and calcium) |
| Fernandez et al. (2020) | Control diet (universal feed) | Acorn-fed Iberian commercial ham | 2 wk | 20 Male Fischer 344 rats (5 wk old) (ulcerative colitis was induced with dextran sulfate sodium in drinking water ad libitum for 1 wk) | Phylum Bacteroidetes, Actinobacteria, Proteobacteria ↑ Firmicutes, Synergistetes, Deferribacteres ↓Family Coriobacteriaceae, Bacteroidaceae, Porphyromonadaceae, Rikenellaceae, Desulfovibrionaceae, Sutterellaceae, Staphylococcaceae, Enterococcaceae, Clostridiaceae Family XIII, Eubacteriaceae, Acidaminococcaceae, Erysipelotrichaceae, Enterobacteriaceae ↑Marinifilaceae, Prevotellaceae, Sphingobacteriaceae, Ruminococcaceae, Lachnospiraceae, Clostridiaceae, Veillonellaceae, Lactobacillaceae, Cohaesibacteriaceae ↓Genus Bacteroides, Butyricimonas, Parabacteroides, Alistipes, Staphylococcus, Enterococcus, Blautia, Dorea, Absiella, Phascolarctobacterium, Parasutterella, Bilophila ↑Prevotella, Mucispirillum, Lactobacillus, Clostridium, Lachnoanaerobaculum, Ruminococcus, Oscillibacter, Desulfovibrio ↓ |