Table 2.
Human studies conducted in relation to prebiotics and newly identified health-promoting bacteria.
| Prebiotic Administered | Study Design | Cohort | Delivery | Effect on Microbiota | Reference |
|---|---|---|---|---|---|
| Extensively studied prebiotics | |||||
| FOS vs. GOS | A randomized, double-blind, cross-over study | 35 healthy participants (10 males, 25 females) | 16 g/d for 14 d | FOS: ↑ Bifidobacterium; and ↓ in Phascolarctobacterium, Enterobacter, Turicibacter, Coprococcus and Salmonella GOS: ↑ in Bifidobacterium; ↓in Ruminococcus, Dehalobacterium, Synergistes & Holdemania |
Liu et al., 201754 |
| GOS | A randomized, double-blind, parallel-group, multisite placebo-controlled study | 62 lactose intolerant subjects | GOS or placebo was escalated in 5-d increments from 1.5 g to 15 g once a day. Taken for 35 d | In response to GOS administration ↑ in Bifidobacterium, Faecalibacterium & Lactobacillus was observed. Subsequent dairy consumption resulted in ↑ Roseburia levels | MA. Azcarte-Peril et al., 201755 |
| Inulin- oligofructose |
Balanced cross-over study | 12 healthy adults split into 2 groups (control and prebiotic) | 10 g prebiotic or control per day over a 16-d period | ↑ F. prausnitzii across all volunteers & ↑ in different Bifidobacterium species dependent on individual as a result of prebiotics | C. Ramirez-Farias et al., 200956 |
| Inulin/oligofructose mix (50:50) | A double blind, placebo controlled, intervention study | 30 obese women | 16 g prebiotic or control per day for 3 months | Prebiotics led to ↑ in bifidobacteria & F. prausnitzii while ↓ in Bacteroides intestinalis, Propionibacterium & Bacteroides vulgatus was observed | EM. Dewulf et al., 201353 |
| Inulin-type fructans | A randomized, double-blind, placebo-controlled, cross-over trial | 42 healthy adults | 12 g chicory-derived Orafti inulin or control per day for 4 weeks | Inulin consumption led to ↑ Bifidobacterium & Anaerostipes abundances while Bilophila numbers ↓ | Vandeputte et al., 201757 |
| Potential prebiotics | |||||
| Red wine polyphenols | A randomized, crossover-controlled intervention study | 10 obese subjects with metabolic syndrome (MetS) and 10 healthy controls | Initial wash-out followed by two intervention periods where participants drank red wine (272 mL/d) or de-alcoholised red wine (272 mL/d) separated with a wash-out phase (15 d) in between cross-over | In healthy individuals ↑ levels in F. prausnitzii & Roseburia after red wine and de-alcoholised red wine consumption in comparison to baseline levels. MetS patients also had ↑ levels in these bacteria while also in Blautia coccoides-E. rectale group and Lactobacillus. Also, differences in microbiota between both groups were significantly ↓ after interventions | I. Moreno-Indias et al., 201658 |
| Red wine polyphenols | A randomized, crossover, controlled, intervention study | 10 healthy males | After a 15-d wash-out period, each participant completed 3 consecutive 20-d periods in which they drank de-alcoholised red wine (272ml/d), red wine (272ml/d), or gin (100ml/d) | Red wine polyphenols ↑ Enterococcus, Prevotella, Bacteroides, Bifidobacterium, Bacteroides uniformis, Eggerthella lenta & Blautia coccoides – Eubacterium rectale groups | M. I. Queipo-Ortuño et al., 201259 |
| Cocoa flavanols | A randomized, double-blind, crossover, controlled intervention study | 22 healthy volunteers | Subjects either consumed high cocoa flavanol (HCF – 494 mg) or low cocoa flavanol (LCF – 29 mg) drink per day for 4 wks followed by 4 wk washout period before switching to alternate drink | HCF ↑ Bifidobacterium & Lactobacilli levels while ↓ levels of C. histolyticum group. Both HCF & LCF led to slight ↑ in E. rectale-C. coccoides group but no significant differences between the two | X. Tzounis et al., 201160 |
| XOS | A double-blind, randomized, placebo-controlled study | 32 healthy subjects | 1.4 g XOS, 2.8 g XOS or placebo taken daily | Both XOS doses ↑ bifidobacteria, no change in lactobacilli, ↑ in Faecalibacterium sp. & Akkermansia sp. in those supplemented with the higher dose | S. Finegold et al., 201461 |
| Resistant starch (RS) | A randomized, crossover dietary study | 39 subjects with reduced insulin sensitivity | Participants either consumed a high (HC) or low carbohydrate (LC) diet followed by a baseline diet. Then the HC subjects consumed either a high RS (HRS – 66 g/d) or low RS (LRS – 4 g/d). Subjects which consumed LC diet consumed either 48 g for HRS or 3 g for LRS | HRS led to ↑ in the ratio of Firmicutes to Bacteroidetes in comparison to LRS. In particular there were ↑ levels of F. prausnitzii, Ruminococcus, Roseburia, E. rectale & A. muciniphila | TV. Maier et al., 201762 |
| Resistant Starch (RS) type 2 | A balanced study | 20 healthy young adults (10 male & 10 female) | 48 g of potato starch (24 g twice per day) for 7 d after a 3-d acclimatization period | Individuals with high or enhanced levels of butyrate concentrations showed ↑ in B. adolescentis or R. bromii after RS consumption. In 5 individuals an ↑ in E. rectale was observed. Huge inter-individual variation was evident | Venkataraman et al., 201626 |