TABLE 2.

Human dietary intervention studies assessing the effect of fermented food consumption on the composition and/or function of the gut microbiota¹

Citation	Study design	Food product tested in the intervention	Comparison made	Participants	Duration of the intervention	Frequency and dose of the intervention	Effect on the gut microbiota	Other health or physiological observations
Veiga et al. (24)	Parallel-group design	Fermented milk	Microbiota of participants who consumed fermented milk compared with the microbiota of participants who received placebo	28 women patients with IBS aged 20–69 y; 13 consumed fermented milk, 15 consumed placebo	4 wk	125 g, twice daily	Decrease in Bilophila wadsworthia (a pathobiont, P < 0.05), and an increase in butyrate-producing bacteria (P < 0.05). There was also a significant increase in SCFA production (particularly butyrate, P < 0.001) by the gut microbiota.	No other health outcomes were assessed.
Unno et al. (22)	Crossover intervention	Fermented milk	Microbiota after consumption of fermented milk compared with the microbiota after weeks of no intervention (washout)	6 healthy adult women aged 20–24 y	3 wk, followed by 3 wk of no intervention (washout)	140 mL, twice daily	Decrease in members of the Bacteroidetes phylum (P < 0.05) and increase in members of the Firmicutes phylum (P < 0.05).	No other health outcomes were assessed.
Tillisch et al. (23)	Parallel-group design	Fermented milk	Microbiota of participants who consumed fermented milk compared with the microbiota of participants who consumed nonfermented milk, or who received no intervention	36 healthy adult women aged 18–55 y; 12 consumed fermented milk, 11 consumed nonfermented milk, 13 received no intervention	4 wk	125 g, twice daily	There were no significant changes in the gut microbiota composition after the intervention.	After an emotional attention task, consumption of fermented milk resulted in reduced midbrain activity (P < 0.004).
Yilmaz et al. (25)	Parallel-group design	Fermented milk	Microbiota after consumption of fermented milk compared with the microbiota of subjects who received no intervention	45 adult patients (18 y or older) with inflammatory bowel disease; 25 treated with fermented milk, 20 untreated	4 wk	200 mL, twice daily	Lactobacillus counts significantly increased in the feces of the treatment group.	Specifically, in patients with Crohn disease (compared with those with ulcerative colitis in the treatment group), there was a decrease in C-reactive protein and an increase in hemoglobin. In addition, in the last 2 wk, bloating scores were reduced and “feeling good” scores increased (P < 0.05).
Lisko et al. (19)	Parallel-group design	Yogurt	Microbiota after consumption of yogurt compared with the microbiota before consumption of yogurt	6 healthy adults aged 18–54 y	6 wk	250 g, once daily	Nonsignificant shifts in Bifidobacteria spp. were observed.	No other health outcomes were assessed.
Yang and Sheu (26)	Parallel-group design	Yogurt	Microbiota after consumption of yogurt compared with the microbiota before consumption of yogurt	38 Helicobacter pylori–infected and 38 healthy children aged 4–12 y	4 wk	200 mL, twice daily	Intervention reduced the Escherichia coli:Bifidobacterium ratio (P < 0.03) in H. pylori–infected children.	Intervention reduced H. pylori loads (P < 0.05) and elevated serum IgA and pepsinogen II concentrations (P < 0.001).
Firmesse et al. (43)	Before and after design	Camembert cheese	Microbiota after consumption of cheese compared with the microbiota before consumption of cheese	12 healthy volunteers (no age specified)	4 wk	40 g, twice daily	Enterococcus faecalis increased in abundance after the intervention period (P < 0.05).	No other health outcomes were assessed.
Firmesse et al. (27)	Before and after design	Camembert cheese	Microbiota after consumption of cheese compared with the microbiota before consumption of cheese	12 healthy volunteers (no age specified)	4 wk	40 g, twice daily	High concentrations of Lactococcus lactis and Leuconostoc mesenteroides measured in fecal samples during the intervention. L. mesenteroides persisted 15 d after the intervention ended.	Nitrate reductase activity decreased during the intervention.
Clemente-Postigo et al. (44)	Crossover intervention	Red wine	Microbiota of participants who consumed red wine compared with the microbiota of participants who consumed dealcoholized red wine, and gin	10 healthy adult males aged 45–50 y	20 d each, no washouts	272 mL, once daily (red wine and dealcoholized red wine), 100 mL gin once daily	Red wine increased Prevotella abundance (P < 0.01), red wine polyphenols (alcoholized and dealcoholized) increased Bifidobacterium abundance (P < 0.01).	No significant differences were observed for LPS or LBP concentrations between interventions. Reductions in Prevotella and Bifidobacterium correlated with LPS concentrations (P < 0.05 and P < 0.01, respectively).
Queipo-Ortuño et al. (45)	Crossover intervention	Red wine	Microbiota of participants who consumed red wine compared with the microbiotas of participants who consumed dealcoholized red wine, and gin	10 healthy adult males aged 45–50 y	20 d each, no washouts	272 mL, once daily (red wine and dealcoholized red wine), 100 mL gin once daily	Consumption of red wine polyphenols increased specific bacterial genera (e.g., Enterococcus, Prevotella, Bacteroides, and Bifidobacterium, P < 0.05).	Daily intake of red wine polyphenols was observed to decrease systolic and diastolic blood pressures, and triglyceride, total cholesterol, HDL cholesterol, C-reactive protein, and transaminase concentrations (P < 0.05).
Moreno-Indias et al. (46)	Crossover intervention	Red wine	Microbiota of participants who consumed red wine compared with the microbiotas of participants who consumed dealcoholized red wine	10 healthy and 10 obese adult males aged 45–50 y	4 wk, 15-d washout in between	272 mL, once daily (red wine and dealcoholized red wine)	Red wine and dealcoholized red wine (polyphenols) decreased the abundances of Bifidobacteria, Lactobacillus, and butyrate-producing bacteria (P < 0.05) in obese adults. Further, red wine polyphenols reduced LPS-producing bacteria in obese patients (P < 0.05).	Red wine polyphenols were associated with reduction in BMI, weight, and LDL:HDL cholesterol (P < 0.05), among other markers of metabolic syndrome.
Barroso et al. (47)	Parallel-group design	Red wine	Microbiotas of participants in different polyphenol metabolizing groups after consumption of red wine	20 healthy adults (age not specified) grouped according to their polyphenol metabolizing capacity	4 wk	250 mL, once daily	Consumption of red wine increased total diversity of the gut microbiota (P < 0.01). This was driven by specific low-abundant taxa; Slackia (P < 0.001), Gordonibacter, Oscillatoria, and Veillonella (P < 0.05).	No other health outcomes were assessed.
Inoguchi et al. (48)	Crossover intervention	Fermented soybean milk	Microbiota of participants who consumed fermented soybean milk compared with the microbiota of participants who consumed nonfermented soybean milk	10 healthy adults aged 21–25 y; 5 consumed fermented soybean milk, 5 consumed nonfermented soybean milk	2 wk	100 g, once daily	Increase in Lactobacillus and decreased Clostridia after fermented soybean milk consumption (P < 0.05).	Fecal sulfide decreased after fermented soybean milk consumption (P < 0.01).
Cheng et al. (49)	Crossover intervention	Fermented soybean milk	Microbiota of participants who consumed fermented soybean milk compared with the microbiota of participants who consumed nonfermented soybean milk	28 healthy adults aged 20–25 y; 14 consumed fermented soybean milk, 14 consumed nonfermented soybean milk	2 wk	250 mL, twice daily	Decrease in coliform organisms and Clostridium perfringens (P < 0.05), increase in Bifidobacterium and Lactobacillus spp. (P < 0.05).	No other health outcomes were assessed.
Nielsen et al. (30)	Parallel-group design	Lacto-fermented sauerkraut	Microbiota of participants who consumed unpasteurized sauerkraut compared with the microbiota of participants who consumed pasteurized sauerkraut	34 patients with IBS aged 16–65 y; 15 consumed pasteurized sauerkraut, 19 consumed unpasteurized sauerkraut	6 wk, followed by a 2-wk follow-up	75 g, once daily	Both pasteurized and unpasteurized sauerkraut led to significant gut microbiota compositional changes (P < 0.001). Sauerkraut-related LAB were significantly increased in guts of patients who consumed unpasteurized sauerkraut.	Both pasteurized and unpasteurized sauerkraut resulted in decreased IBS severity scores.
Chiu et al. (50)	Parallel-group design	Fermented plant extract	Microbiota of participants who consumed fermented plant extract compared with the microbiota of participants who received placebo	44 patients with hypercholesterolemia aged 30–60 y; 22 received fermented plant extract, 22 received placebo	8 wk, followed by a 2-wk follow-up	30 mL, twice daily	Individuals who consumed the fermented plant extract displayed increased gut Bifidobacteria (P < 0.05) and Lactobacillus spp. (P < 0.01) and decreased E. coli and C. perfringens (P < 0.05).	Consumption of fermented plant extract increased total antioxidant capacity (P < 0.05) and decreased the lipid profile (P < 0.05).
Han et al. (15)	Parallel-group design	Kimchi	Microbiota of participants who consumed fresh kimchi compared with the microbiota of participants who consumed fermented kimchi	23 obese women aged 30–60 y; 12 consumed fresh kimchi, 11 consumed fermented kimchi	8 wk	60 g, thrice daily	Significant increase in Bifidobacterium abundance after kimchi consumption for 8 wk. Nonsignificant shifts in other bacterial taxa.	Negative correlation between Bifidobacterium and waist circumference (P < 0.05). This group also observed upregulation of genes associated with metabolism, immunity, and digestion (P < 0.05), which also correlated with bacterial taxa (P < 0.05).
Yamamoto et al. (32)	Before and after design	Fermented green tea (Cha-Koji)	Microbiota after consumption of Cha-Koji compared with the microbiota before consumption of Cha-Koji	9 healthy adults aged 25–47 y	4 wk	2.14 g, once daily	Increase in Clostridium cluster XIVa and decrease in cluster IX (P < 0.05).	Increase in T regulatory cells after consumption of fermented tea (P < 0.01).
Jaquet et al. (51)	Before and after design	Coffee	Microbiota after consumption of coffee compared with the microbiota before consumption of coffee	16 healthy adults aged 21–57 y	3 wk	3 cups/d	Increase in Bifidobacterium spp. (P < 0.05)	No other health outcomes were assessed.

¹IBS, irritable bowel syndrome; LAB, lactic acid bacteria; LBP, LPS-binding protein.