Modulation of gut microbiota composition by kefir in human and animal models.
| Kefir preparation method | Sample type | Feeding dosage/administration | Experiment duration | DNA extraction | Organ used for microbial analysis | Reference |
|---|---|---|---|---|---|---|
| Commercially available kefir | Professional female soccer players, aged 18–29 years(n = 21) | 200 mL of kefir daily, through oral intake | 28 days | DiaRex® Stool Genomic DNA Extraction Kit (Cat No.: SD-0323, Diagen, Ankara, Turkey) | Fecal samples | Öneş et al. [25] |
| Microbial changes result | ||||||
| ↑ Akkermansia muciniphila, Bifidobacterium, SCFA-related genera (e.g., Roseburia)↓ Proteobacteria | ||||||
| Traditional kefir produced with grains by Danem, Inc. (kefirdanem.com, Suleyman Demirel University Technopark, Isparta, Turkey) | Women with PCOS, aged between 18 and 40 years(n = 17) | 250 mL/day of kefir, through oral administration | 8 weeks | DiaRex® Stool Genomic DNA Extraction Kit | Fecal samples | Çıtar Dazıroğluet et al. [27] |
| Microbial changes result | ||||||
| ↑ Firmicutes, Actinobacteria, and Lactococcus-related taxa↓ Bacteroidetes, Proteobacteria, and Holdemania | ||||||
| Lifeway Foods® Kefir | ICU patients,(> 18 years)(n = 54) | 60 mL, followed by 120 mL after 12 h, then 240 mL of kefir daily, through oral or nasogastric administration | 4 weeks | Qiagen’s DNeasy 96 PowerSoil Pro QIA- cube HT Kit(QIAGEN, Germantown, MD, USA) | Fecal samples | Gupta et al. [28] |
| Microbial changes result | ||||||
| ↑ Bacilli, Lactobacillus spp. (L. plantarum, L. reuteri, L. rhamnosus), Parvimonas and Dialister↓ Bifidobacterium longum | ||||||
| Kefir milk product (provided by Nourish Kefir) | Healthy volunteers, aged from 18 to 65(n = 9) | 247 mL/day of kefir, through oral intake | 28 days | QIAamp DNA Stool Mini Kit (QIAGEN, UK) | Fecal samples | Walsh et al. [26] |
| Microbial changes result | ||||||
| ↑ Lactococcus raffinolactis | ||||||
| Commercial kefir (the brand is not mentioned) | Angora cats, age: 3.3 ± 2.5 years old(n = 7; male: 5, female: 2) | 30 mL/kg/day of kefir, orally administered | 14 days | Selective media for total mesophilic aerobic bacteria, coliform bacteria, Enterobacteriaceae, Enterococcus spp., Lactobacillus spp., Lactococcus spp., and yeast) | Fecal samples | Kabakçi et al. [31] |
| Microbial changes result | ||||||
| ↑ Total mesophilic aerobic bacteria, Lactobacillus spp., Lactococcus spp., and yeast↓ Enterococcus spp. | ||||||
| Kefir grains were cultured in Irish whole full-fat cow’s milk | Male BTBR T+ Itpr3tf/J mice, 5–6 months of age(n = 9) | 0.2 mL/day of kefir, through oral administration | 3 weeks | QiaAmp PowerFecal Pro DNA Kit | Cecal contents | van de Wouw et al. [29] |
| Microbial changes result | ||||||
| ↑ Lachnospiraceae bacterium A2↓ Clostridiaceae and Clostridium | ||||||
| Kefir grains were independently cultured in Irish whole full-fat cow’s milk to prepare two distinct kefir types, Fr1 and UK4 | Male C57BL/6J mice, 8 weeks of age(n = 48) | 0.2 mL/day, through oral gavage | 3 weeks | Using QIAamp PowerFaecal DNA Kit | ileal, caecal, and faecal samples | van de Wouw et al. [30] |
| Microbial changes result | ||||||
| Both kefir groups: ↑ Lactobacillus reuteri (caecum and faeces), Eubacterium plexicaudatum (faeces and caecum), Bifidobacterium pseudolongum (ileum and caecum)↓ Lachnospiraceae bacterium 3_1_46FAA (caecum), Propionibacterium acnes (faeces), Bacillus amyloliquefaciens (faeces)For Fr1 kefir group: ↑ Parabacteroides goldsteinii (caecum), Bacteroides intestinalis (faeces), Anaerotruncus spp. (faeces), Parabacteroides goldsteinii (faeces)For the UK4 kefir group: ↑ Alistipes spp. (caecum)↓ Candidatus Arthromitus spp. (ileum) | ||||||
| Kefir peptides (KPs), fermented goat milk with traditional kefir grains | Female C57BL/6J mice (ovariectomized model, simulating estrogen deficiency)(n = 6) | 0.1 mL/kg daily of KPs, through oral administration | 8 weeks | QIAamp PowerFecal DNA Kit (Qiagen, Redwood, CA, USA) | Cecal contents | Tu et al. [33] |
| Microbial changes result | ||||||
| ↑ Alloprevotella, Anaerostipes, Parasutterella, Romboutsia, Ruminococcus, and Streptococcus | ||||||
| Sterilized milk was fermented with kefir grains | Healthy adult dogs, 5.17 ± 2.32 years old(n = 6; male: 4, female: 2) | 200 mL of kefir daily, through oral administration | 2 weeks | NucliSENS easyMAG instrument (bioMérieux, Marcy l’Etoile, France) | Fecal samples | Kim et al. [32] |
| Microbial changes result | ||||||
| ↑ Prevotellaceae, Selenomonadaceae, Sutterellaceae, Catenibacterium mitsuokai, and LAB.↓ Clostridiaceae, Fusobacteriaceae, Ruminococcaceae, Bacteroides uniformis, Fusobacterium mortiferum, Pseudoflavonifractor capillosus, and Fusicatenibacter saccharivorans | ||||||
| Kefir was prepared using the culture of DC1500I (Danisco, Olsztyn, Poland) | Adults with metabolic syndrome, aged 18–65 years(n = 12) | 180 mL/day of kefir, consumed orally | 12 weeks | Qiagen Stool Mini Kit (Qiagen, Hilden, Germany) | Fecal samples | Bellikci-Koyu et al. [24] |
| Microbial changes result | ||||||
| ↑ Firmicutes, Verrucomicrobia, Actinobacteria, Bacteroides, Clostridia, Lactobacillales, Bifidobacterium, and the Firmicutes/Bacteroidetes ratio↓ Bacteroidetes, Proteobacteria, Prevotellaceae, Alistipes, and Veillonellaceae | ||||||
| Cow milk fermented with kefir grains vs. kefir starter culture | Male BALB/c mice(n = 30) | 0.3 mL/day of kefir, through oral gavage | 15 days | Selective culture media for Lactobacilli, LAB, lactic streptococci, yeasts/fungi, Bifidobacterium spp., and Enterobacteria | Fecal samples | Erdogan et al. [34] |
| Microbial changes result | ||||||
| Kefir grains group:↑ Lactobacillus spp., Streptococci, Lactobacillus acidophilus, Bifidobacterium spp., and yeastKefir starter culture group: ↓ Lactobacillus spp., Streptococci, Lactobacillus acidophilus, and Bifidobacterium spp. | ||||||
↑: increase; ↓: decrease; ICU: intensive care units; LAB: lactic acid bacteria; PCOS: polycystic ovary syndrome; SCFA: short-chain fatty acid; UK4 and Fr1: two types of kefirs made from different kefir grain communities.