. 2022 Dec 7;9:1003620. doi: 10.3389/fnut.2022.1003620

Table 4.

Systematic review study outcomes of included studies that attempted to determine the impact of prebiotic, probiotic, and synbiotic supplementation on gastrointestinal outcomes at rest.

References	N and study design	Supplement/ comparator	Intervention ingredient/s and supplement duration	Outcome measure/s (Δ in mean/median from pre- to post-supplementation period unless otherwise indicated)
Intestinal permeability
Russo et al. (62)	N = 20 Study design: RXT	Prebiotic vs. placebo	Inulin-enriched pasta, 5 wk	Urinary lactulose/mannitol ratio: Int ↓ 0.02, Pla ↔ 0.00 (p < 0.05). Serum zonulin: Int ↓ 1.61 ng/ml, Pla ↑ 0.35 ng/ml (p < 0.05). Fecal zonulin: Int ↑ 0.01 μg/g, Pla ↔ 0.00 μg/g^NS
Axelrod et al. (63)	n = 7 RXT	Probiotic vs. placebo	L. salivarius UCC118, 4 wk	Fecal zonulin: Int ↓ 0.18 mg/dL, Pla ↓ 0.2 mg/dL ^NS
Lamprecht et al. (76)	n = 23 RCT	Probiotic vs. placebo	B. bifidum W23, B lactis W51, E. faecium W54, L. acidophilus W22, L. brevis W63, L. lactis W58, 14 wk	Fecal zonulin: Int ↓ 8.8 ng/ml, Pla ↑ 1.6 ng/ml (p = 0.019)
Townsend et al. (88)	n = 25 RCT	Probiotic vs. placebo	Bacillis subtilis DE111, 12 wk	Serum zonulin: Int ↑ 0.2 ng/ml, Pla ↑ 0.2 ng/ml^NS
Roberts et al. (94)	n = 20 RCT	Synbiotic vs. prebiotic	L. acidophilus CUL-60 (NCIMB 30157), L. acidophillus CUL-21 (NCIMB 30156), B. bifidum CUL-20 (NCIMB 30172), B. animalis subspecies lactis CUL-34 (NCIMB 30153, Fructooligosaccharides, 12 wk	Urinary lactulose/mannitol ratio: Int ↑ 0.011, Pla ↑ 0.029^NS
West et al. (98)	n = 22 RCT	Synbiotic vs. prebiotic	L. paracasei subs Paracasei (L. casei 431^®), B. animalis ssp. lactis (BB-12^®), L. acidophilus LA-5, L. rhamnosus GG, Raftiline, Raftilose GR, 3 wk	Lactulose/mannitol ratio: ^NSbetween groups (data not reported)
Endotoxin responses
Burton et al. (66)	n = 13 RXT	Probiotic vs. placebo	S. thermophilus, L. delbrueckii spp. Bulgaricus, L. rhamnosus GG, 2 wk	LPS: Int ↓ 0.3 pg/ml, Pla ↓ 0.05 pg/ml^NS
Gill et al. (68)	n = 8 RXT	Probiotic vs. placebo	L. casei, 1.0 × 10¹¹ cells/bottle Commercial supplement, taken twice daily for 7 days	Gram negative endotoxin: Int ↑ 0.1 EU/ml, Pla ↑ 0.3 EU/ml^NS
Carbuhn et al. (67)	n = 17 RCT	Probiotic vs. placebo	B. longum 35624, 6 wk	LPS: ^NSbetween groups (data not reported) LBP: ^NSbetween groups (data not reported)
Roberts et al. (94)	n = 20 RCT	Synbiotic vs. placebo	L. acidophilus CUL-60 (NCIMB 30157), L. acidophillus CUL-21 (NCIMB 30156), B. bifidum CUL-20, B. animalis subspecies lactis CUL-34 (NCIMB 30153), Fructooligosaccharides, 12 wk	Endotoxin units: Int ↓ 2.30 pg/ml, Pla ↓ 0.84 pg/ml ^NS IgG endotoxin antibodies (anti-LPS): Int ↑ 42 MU/ml, Pla ↓ 42 MU/ml^NS
Cytokine responses
Axelrod et al. (63)	n = 7 RXT	Probiotic vs. placebo	L. salivarius UCC118, 4 wk	IL-6: (ΔΔ pre to post-exercise, pre to post-intervention) Int ↑ 0.5 pg./ml, Pla: ↑ 1.4pg/ml^NS
Batatinha et al. (65)	n = 27	Probiotic vs. placebo	B. animalis. Lactis 10 × 10⁹; L. Acidophilus 10 × 10⁹ 1 sachet daily for 30 days	IL-10: (baseline to pre-ex Δ) Int: ↓ 5.5 ng/ml, Pla: ↓ 3.2 ng/ml^NS IL-4: Int: ↓ 3.0 ng/ml, Pla: ↓ 0.9 ng/ml^NS IL-6: Int: ↔ 0 ng/ml, Pla: ↓ 2.5 ng/ml^NS IL-2: Int: ↓ 0.4 ng/ml, Pla: ↓ 2.6 ng/ml^NS IL-15: Int: ↓ 0.4 ng/ml, Pla: ↓ 0.6 ng/ml^NS IL-8 (ng/ml): Int: ↑ 0.4 ng/ml, Pla: ↓ 3.8 ng/ml^NS IL-1β: Int: ↓ 0.7 ng/ml, Pla: ↓ 0.8 ng/ml^NS TNF-α: Int: ↓ 2.2 ng/ml, Pla: ↓ 3.7 ng/ml^NS IFN-γ : Int: ↓ 2.6 ng/ml, Pla: ↓ 9.0 ng/ml^NS
Burton et al. (66)	n = 13 RXT	Probiotic vs. placebo	S. thermophilus, L. delbrueckii spp. Bulgaricus, L. rhamnosus GG, 2 wk	TNF-α: Int ↑ 0.75 pg/ml, Pla ↑ 0.95 pg/ml^NS IL-6: Int ↓ 0.45 pg/ml, Pla ↑ 0.65 pg/ml^NS CCL2: Int ↑ 1.8 pg/ml, Pla ↑ 12.55 pg/ml (p = 0.01) CCL5: Int ↓ 12.75 pg/ml, Pla ↓ 7.6 pg/ml^NS
Carbuhn et al. (67)	n = 17 RCT	Probiotic vs. placebo	B. longum 35624, 6 wk	IL-1ra: Int ↓ 107 pg/ml, Pla ↓ 37 pg/ml^NS IFN-γ, IL-1B, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, IL-17, IL-17F, and IL-22, TNF-α_ were below detectable levels in assay.
Gill et al. (68)	n = 8 RXT	Probiotic vs. placebo	L. casei, 1 wk	IL-6: Int ↑ 0.1 pg/ml, Pla ↑ 0.4 pg/ml^NS IL-1β: Int ↓ 0.05 pg/ml, Pla ↓ 0.02 pg/ml^NS TNF-α: Int ↓ 0.1 pg/ml, Pla ↑ 0.2 pg/ml^NS IFN-γ: Int ↑ 0.1 pg/ml, Pla ↑ 0.7 pg/ml^NS IL-10: Int ↑ 1.2 pg/ml, Pla ↑ 4.8 pg/ml^NS IL-8: Int ↔ 0.0 pg/ml, Pla ↑ 0.3 pg/ml^NS
Hoffman et al. (73)	n = 15 RCT	Probiotic vs. placebo	Inactivated Bacillus coagulans; 2 wk	IFN-γ : Int: ↓ 0.2 pg/ml, Pla: ↓ 3.6 pg/ml^NS IL-10 : Int: ↑ 0.4 pg/ml, Pla: ↓ 1.4 pg/ml^NS IL1-B: Int: ↑ 0.3 pg/ml, Pla: ↑ 2.8 pg/ml^NS IL-2: Int: ↓ 0.3 pg/ml, Pla: ↓ 0.3 pg/ml^NS IL-6: Int: ↓ 0.2 pg/ml, Pla: ↓ 1.0 pg/ml^NS IL-8: Int: ↓ 2.4 pg/ml, Pla: ↓ 3.6 pg/ml^NS TNF-α: Int: ↓ 1.7 pg/ml, Pla: ↓ 4.5 pg/ml^NS
Lamprecht et al. (76)	n = 23 RCT	Probiotic vs. placebo	B. bifidum W23, B lactis W51, E. faecium W54, L. acidophilus W22, L. brevis W63, L. lactis W58, 14 wk	TNF-α: Int ↓ 17.1 pg/ml, Pla ↑ 4.7 pg/ml^NS IL-6: Int ↓ 1.0 pg/ml, Pla ↑ 0.1 pg/ml^NS
Schreiber et al. (82)	n = 27 RCT	Probiotic vs. placebo	L. helveticus Lafti L10, B. animalis ssp. lactis Lafti B94 E. faecium R0026, B. longum R0175 Bacillus subtilis R0179, 90 days	ANCOVA, (Δ) changes from baseline, adj. for training loads. IL-6 adj: Int: 0.11 ± 0.64, Pla: −0.25 ± 0.6^NS TNF-α adj: Int: −0.02 ± 0.23, Pla: 0.06 ± 0.21^NS CRP adj: Int: 443.82 ± 238.73, Pla: 231.55 ± 381.28^NS
Smarkusz-Zarzecka et al. (83)	n = 66 RCT	Probiotic vs. placebo	B. lactis W52, L. brevis W63, L. casei W56, Lactococcus lactis W19, Lactococcus lactis W58, L. acidophilus W37, B. bifidum W23, L. salivarius W24. 3 months	CRP: Male: Δ: Int: ↓0.12 mg/L, Pla: ↓ 0.31 mg/L^NS Female Δ: Int: ↓1.3 mg/L, Pla: ↓ 0.6 mg/L^NS TNF-α: Male: Δ: Int: ↓ 1.62 mg/L, Pla: ↓ 0.88 mg/L^NS Female: Δ: Int: ↓ 1.43 mg/L, Pla: ↓1.72 mg/L^NS
Tavares-Silva et al. (87)	n = 14 RCT	Probiotic vs. placebo	Gelatinous capsules: Lactobacillus acidophilus-LB-G80, Lactobacillus paracasei-LPc-G110, Lactococcus subp. lactis-LLL-G25, Bifidobacterium animalis subp. lactis-BL-G101, Bifidobacterium bifidum-BB-G90; 30 days	IL-2 (Baseline to 24 h before marathon) Int: ↓ 0.37 pg/ml (p < 0.04), Pla: ↓ 0.2 pg/ml^NS IL-4 (Baseline to 24 h before marathon) Int: ↓ 0.73 pg/ml^NS, Pla: ↓ 0.89 pg/ml (p < 0.04) IL-10 (Baseline to 24 h before marathon) Int: ↓ 0.97 pg/ml (p < 0.001), Pla: ↓ 0.05 pg/ml^NS TNF-α (Baseline to 24 h before marathon) Int: ↑ 0.09 pg/ml^NS, Pla: ↓0.05 pg/ml^NS
Townsend et al. (88)	n = 25 RCT	Probiotic vs. placebo	Bacillis subtilis DE111, 12 wk	TNF-α: Int: Δ: ↓ 0.25 pg/ml, Pla: Δ: ↑ 0.36 pg/ml Int ↓ Pla, p = 0.024 IL-10: Int: Δ: ↑ 0.1 pg/ml, Pla Δ: ↑ 0.15 pg/ml^NS
Vaisberg et al. (89)	n = 42 RCT	Probiotic vs. placebo	L. casei Shirota, 30 days	IL-1β: Int ↑ 22.7 pg/ml, Pla ↑ 20.9 pg/ml^NS IL-1ra: Int ↑ 16.3 pg/ml, Pla ↑ 10.5 pg/ml^NS IL-4: Int ↑ 9.4 pg/ml, Pla ↑ 11.3 pg/ml^NS IL-5: Int ↑ 7.2 pg/ml, Pla ↑ 6.7 pg/ml^NS IL-6: Int ↑ 4.4 pg/ml, Pla ↑ 0.9 pg/ml^NS IL-10: Int ↑ 5.7 pg/ml, Pla ↑ 2.6 pg/ml^NS IL-12p70: Int ↑ 6.9 pg/ml, Pla ↑ 3.6 pg/ml^NS IL-13: Int ↑ 7.3 pg/ml, Pla ↑ 6.9 pg/ml^NS TNF-α: Int ↑6.6 pg/ml, Pla ↑ 22.2 pg/mL^NS
Quero et al. (93)	n = 27 RCT	Synbiotic vs. placebo	B. lactis CBP-001010, L. rhamnosus CNCM I-4036, B. longum ES1, Fructooligosaccharides, 30 days	IL-1β: Sedentary: Int: ↑ 0.3 pg/mL (p < 0.01), Pla: ↑ 0.1 pg/mL^NS Athletes: Int: ↓ 0.2 pg/mL^NS, Pla: ↓ 0.2 pg/mL^NS IL-10 Sedentary: Int: ↓ 0.3 pg/mL (p < 0.01), Pla: ↓ 0.4 pg/mL (p < 0.05) Athletes: Int: ↑ 0.05 pg/mL^NS, Pla: ↓ 0.05 pg/mL^NS
West et al. (98)	n = 22 RCT	Synbiotic vs. prebiotic	L. paracasei subs Paracasei (L. casei 431^®), B. animalis ssp. lactis (BB-12^®), L. acidophilus LA-5, L. rhamnosus GG, Raftiline, Raftilose GR, 3 wk	IL-16: 50% greater increase in Pre vs. Syn (p = 0.02) IL-18: ^NSbetween pre and syn, no additional data shown IL-12 and IFN-γ: Undetectable in assay
Gastrointestinal function
Damen et al. (55)	n = 27 RXT	Prebiotic vs. placebo	Arabinoxylan oligosaccharides (AXOS), 3 wk	Defecation frequency: Int ↓ 0.1/day, Pla ↑ 0.1/day (p < 0.05) Bristol stool form scale: Int ↓ 0.1/day, Pla ↑ 0.2/day^NS
Kleessen et al. (59)	n = 45 RCT	Prebiotic vs. prebiotic vs. placebo	Chicory inulin (CH) or Jerusalem artichoke inulin (JA), 3 wk	Defecation frequency: CH ↑ 3/wk (p < 0.05), JA ↑ 2/wk (p < 0.05), Pla ↑ 2/wk (p < 0.05) Stool consistency (1–4 scale, hard to soft): CH: ↑ 2 (p < 0.05), JA: ↑ 3 (p < 0.05), Pla: ↑ 1^NS
Russo et al. (61)	n = 20 RXT	Prebiotic vs. placebo	Inulin-enriched pasta, 5 wk	Ultrasound full gastric emptying time: Int ↑ 30 min (p < 0.05), Pla ↔ 0 min^NS Electrogastrography (% normal slow waves): Pre-Prandial: Int ↑ 12.5%, Pla ↑ 6.5% (p = 0.05) Post-prandial: Int ↑ 5.6%, Pla ↑ 2.0% (p = 0.03)
Russo et al. (45)	n = 20 RXT	Prebiotic vs. placebo	Inulin-enriched pasta, 5 wk	Ultrasound half gastric emptying time: Int ↑ 8.3 min (p < 0.05), Pla ↑ 1.4 min^NS
Reimer et al. (60)	N = 48 RXT	Prebiotic vs. Prebiotic vs. placebo	Chicory inulin type fructans (ITF), 4 wk	Stools/d (Δ c/f baseline): Int 1: −0.1 ± 0.2, Con 1: 0.3 ± 0.2^NS Int 2: −0.1 ± 0.2, Con 2: 0 ± 0.1^NS Bristol Stool Rating [(1–7) Δ c/f baseline]: Int 1: −0.1 ± 0.3, Con 1: −0.4 ± 0.3^NS Int 2: −0.1 ± 0.3, Con 2: 0 ± 0.3^NS
Bacterial taxa
Damen et al. (55)	n = 27 RXT	Prebiotic vs. placebo	Arabinoxylan oligosaccharides (AXOS), 3 wk	FISH analysis to count number of different bacterial groups. Total bacteria cell counts were determined by 4′-6-diamidino-2-phenylindole. ^NSChanges in abundance or diversity between groups or pre-post supplementation in the same group
Finegold et al. (56)	n = 32 RCT	Prebiotic vs. Prebiotic vs. placebo	Xylooligosaccharides (XOS), 8 wk	Bacterial diversity (Operational Taxonotic Units, species level and Shannon index): ^NSin α-diversity (OTU) or Shannon index. 16S rRNA gene sequencing/log₁₀ scale of bacterial counts (CFU/g) ↑Bifidobacterium count in high dose XOS only (p < 0.05) ↑Bacteroides fragilis in high dose XOS only (p < 0.05) ↑ total anaerobes count in high dose XOS only (p < 0.05) ^NSFor total aerobes, Lactobacillus, Enterobacteriaceae, and Clostridium counts cf. baseline in all groups ↓Enterobacteriaceae count cf placebo after washout (p < 0.05)
François et al. (57)	n = 63 RXT	Prebiotic vs. Prebiotic vs. placebo	Arabinoxylan oligosaccharides (AXOS), 3 wk	FISH analysis to count number of different bacterial groups. Total bacteria cell counts were determined by 4'-6-diamidino-2-phenylindole. Percentage of bifidobacterial calculated as the ratio of the absolute amounts of bifidobacteria to the total bacterial cell count. Bifidobacteria (log₁₀ counts/g dry weight feces): High: 9.3, Low: 9.0, Pla: 8.9 High vs. Low p < 0.05 High vs. Pla p < 0.001^NS for Lactobacilli, Faecalibacterium prausnitzii, Clostridium histolyticum–lituseburense or Roseburia–Eubacterium rectale
Kleessen et al. (59)	n = 45 RCT	Prebiotic vs. prebiotic vs. placebo	Chicory inulin (CH) or Jerusalem artichoke inulin (JA), 3 wk	Bacterial counts were assessed by fluorescent in situ hybridization or colony forming units, as assessed by conventional culture methods.
				All data expressed in log¹⁰ counts/g wet weight feces Total bacteria: CH: ↑ 0.1, JA: ↔0, Pla: ↔0, ^NSClostridium coccoides/Eubacterium rectale cluster : CH: ↓ 0.6 (p < 0.05), JA: ↓ 0.6 (p < 0.05), Pla: ↓0.3, ^NSBacteroides/Prevotella: CH: ↓ 0.4 (p < 0.05), JA: ↓ 0.6 (p < 0.05), Pla: ↑ 0.1 CH and JA both > Pla (p < 0.05) Faecalibacterium prausnitzii: CH: ↓ 0.2, JA: ↓ 0.2, Pla: ↓ 0.1, ^NSBifidobacterium: CH: ↑ 1.2, JA: ↑ 1.2, Pla: ↑ 0.3 CH and JA both > Pla (p < 0.05) Atopobium group: CH:↔ 0, JA: ↓ 0.2, Pla: ↔ 0, ^NSLactobacillus: CH: ↓ 0.9, JA: ↓ 0.5, Pla: ↓ 0.7, ^NSEnterococcus: CH: ↓ 0.9, JA: ↓ 0.4, Pla: ↑ 0.4, ^NSEnterobacteriaceae: CH: ↓ 0.4, JA: ↓ 0.9, Pla: ↓ 0.7^NS
Reimer et al. (60)	n = 48 RXT	Prebiotic vs. Prebiotic vs. placebo	Chicory inulin type fructans (ITF), 4 wk	Results are expressed as relative abundance (%) of Bifidobacterium per total bacteria (Bifidobacterium 16S rRNA gene copies × 100/total 16S rRNA gene copies). Bacterial diversity ^NSin α-diversity. Community Structure ^NS in β-diversity Microbial abundance (phylum) (Con = > Int 1/Int 1 = > Con) Actinobacteria: Con: 6.02 ± 5.26 Int 1: 15.23 ± 12.37, ↑ 153% p < 0.01(adj) Int: 11.70 ± 8.65 Con: 6.36 ± 3.95 ↓ 83% p < 0.01(< adj) Firmicutes Con: 85.91 ± 9.02 Int 1: 78.72 ± 10.96, ↓ 8% p < 0.01(adj) Int: 82.52 ± 9.58 Con: 88.13 ± 4.37 ↑ 6% p < 0.01(adj) Bacteroidetes Con: 6.51 ± 7.96 Int 1: 3.48 ± 4.26, ↓ 46% p = 0.05(adj) (Con = > Int 2/Int 2 = > Con) Actinobacteria Con: 8.07 ± 7.38 Int 2: 13.19 ± 12.37 0.01 ↑ 63% ^NSProteobacteria Con: 0.79 ± 1.29 Int 2: 0.38 ± 0.39 0.04 ↓ 51%^NS Family (Con ≥ Int 1/Int 1 ≥ Con) Bifidobacteriaceae Con: 2.52 ± 2.90 Int 1: 10.28 ± 9.09, p < 0.01(adj) ↑ 308% p < 0.01(adj) 7.57 ± 8.08 2.63 ± 1.88 ↓ 65% p < 0.01(adj)
				Actinomycetaceae Con: 0.06 ± 0.09 Int 1: 0.24 ± 0.29 ↑ 300% p < 0.01(adj) Int 1: 0.23 ± 0.24 Con: 0.09 ± 0.08 ↑ 60% p < 0.01(adj) Microbacteriaceae Con: 0.003 ± 0.01 Int 1: 0.01 ± 0.02 ↑ 233% p < 0.01(adj) Int 1: 0.01 ± 0.02 0.0006 ± 0.003 ↓ 94% p < 0.05(adj) Cellulomonadaceae Con: 0.0003 ± 0.002 Int 1: 0.01 ± 0.01 ↑ 3,233% p < 0.01(adj) Micrococcaceae Con: 0.06 ± 0.10 Int 1: 0.19 ± 0.33 ↑ 216% p < 0.01(adj) Brevibacteriaceae Con: 0.01 ± 0.03 Int 1: 0.03 ± 0.05 ↑ 200% p < 0.01(adj) Family (Con ≥ Int 2/Int 2 ≥ Con) Micrococcaceae Con: 1.18 ± 1.72 Int 2: 2.37 ± 2.67 ↑ 101%^NS
				Vibrionaceae Con: 0.21 ± 0.44 Int 2: 0.05 ± 0.08 ↓ 76%^NS Bifidobacteriaceae Con: 1.17 ± 1.91 Int 2: 2.39 ± 3.63 ↑ 104%^NS Enterobacteriaceae Con: 0.42 ± 0.93 Int 2: 0.10 ± 0.17 ↓ 76^NS Actinomycetaceae Con: 0.44 ± 0.77 Int 2: 0.88 ± 1.44 ↑ 100%^NS Genus (Con ≥ Int 1/Int 1 ≥ Con) Bifidobacterium Con: 5.30 ± 5.87 Int 1: 18.73 ± 14.99, ↑ 253% p < 0.01(adj) Int 1: 11.91 ± 12.02 Con: 4.63 ± 3.42 ↓ 61% p < 0.01(adj) Actinomyces Con: 0.13 ± 0.18 Int 1: 0.45 ± 0.49, ↑ 246% p < 0.01(adj) Int 1: 0.37 ± 0.38 Con: 0.16 ± 0.15 ↓ 56% p < 0.02(adj) Cellulomonas Con: 0.0007 ± 0.01 Int 1: 0.01 ± 0.03 ↑ 1,328% p < 0.02(adj) Nesterenkonia Con: 0.12 ± 0.21 Int 1: 0.35 ± 0.54 ↑ 191% p < 0.03(adj) Lachnospira Con: 2.20 ± 2.70 Int 1: 0.93 ± 1.36 ↓ 57% p < 0.04(adj) Oscillospira Con: 1.11 ± 1.01 Int 1: 0.65 ± 0.54 ↓ 41% p < 0.04(adj) Brevibacterium Con: 0.03 ± 0.05 Int 1: 0.06 ± 0.08 ↑ 100% p < 0.04(adj) Genus (Con = > Int 2) Nesterenkonia Con: 2.46 ± 3.32 Int 2: 4.86 ± 4.75 ↑ 97% ^NS Vibrio Con: 0.50 ± 1.12 Int 2: 0.10 ± 0.16 ↓ 80% ^NS Bifidobacterium Con: 2.47 ± 3.83 Int 2: 4.62 ± 6.13 ↑ 87%^NS Actinomyces Con: 0.91 ± 1.53 Int 2: 1.67 ± 2.46 ↑ 83%^NS
Axelrod et al. (63)	n = 7 RXT	Probiotic vs. placebo	L. salivarius UCC118, 4 wk	DNA extraction by shotgun metagenomic sequencing. Shannon and Simpson index ^NSin α-diversity or richness. Probiotic data only, no placebo data available Phyla: Verrucomicrobia ↓ 0.144% (q = 0.001) Genus: Prosthecobacter ↓ 0.141% (q = 0.004) Species: fusiformis ↓ 0.051% (q = 0.006)
Burton et al. (66)	n = 13 RXT	Probiotic vs. placebo	S. thermophilus, L. delbrueckii spp. Bulgaricus, L. rhamnosus GG, 2 wk	16S rRNA gene sequencing Relative abundance compared to baseline S. salivarius spp. thermophilus: Int ↑ 0.10%, Pla ↔ 0.0% (p < 0.05) L. delbrueckii spp. Bulgaricus: Int ↑ 0.02%, Pla ↔ 0.0% (p < 0.05) L. rhamnosus GG: Int ↔ 0.0%, Pla ↔ 0.0% ^NS Bilophila wadsworthia: Int ↓ 0.07%, Pla ↓ 0.27% ^NS B. kashiwanohense/B. pseudocatenulatum: Int ↓ 0.05%, Pla ↑ 0.05% (p < 0.05)
Huang et al. (74)	n = 20 male RCT	Probiotic vs. placebo	L. plantarum PS128, 4 wk	16S rRNA gene sequencing No baseline data reported. % Relative abundance (Phyla) Int: Fermicutes 46.6%, Bacteriodetes 47.0%, Proteobacteria 3.8%, Actinobacteria 2.1%, Fusobacteria 0.3% Pla: Fermicutes 50.3%, Bacteriodetes 41.6%, Proteobacteria 4.9%, Actinobacteria 1.0%, Fusobacteria 1.5% ^NS between groups. Relative abundance (Genus) Anaerotruncus (× 10⁻⁴) Int 0, Pla 1.0; Caproiciproducens (× 10⁻⁴) Int 0.1, Pla 1.0; Coprobacillus (× 10⁻⁵) Int 0, Pla 3.3; Desulfovibrio (× 10⁻⁵), Int 0, Pla 5.9; Dielma (× 10⁻⁵), Int 0, Pla 2.6; Family_XIII_UCG_001 (× 10⁻⁵), Int 0.9, Pla 9.2; Holdemania (× 10⁻⁵), Int 0.6, Pla 7.2; Oxalobacter (× 10⁻⁵), Int 0, Pla 6.1; Int < Pla (p < 0.05) Akkermansia (× 10⁻³), Int 5.0, Pla 1.3; Bifidobacterium (× 10⁻²), Int 1.5, Pla 0.8; Butyricimonas (× 10⁻³), Int 4.7, Pla 2.3; Lactobacillus (× 10⁻³), Int 1.7, Pla 0.7; Int > Pla (p < 0.05)
Klein et al. (75)	n = 26 RXT	Probiotic vs. placebo	B. lactis 420x, L. acidophilus 74-2, 5 wk	Preparation of fecal samples by FISH analysis. Relative abundance compared to baseline B. lactis: Int ↑ 1.43%, Pla ↑ 0.39% (p < 0.05) L. acidophilus: Int ↑ 0.18%, Pla ↑ 0.02% (p < 0.05)
Lee et al. (77)	n = 16 RCT	Probiotic vs. placebo	L. paracasei DSM 32785 (LPC12), L. rhamnosus DSM 32786 (LRH10), L. helveticus DSM 32787 (LH43), L. fermentum DSM 32784 (LF26), and S. thermophilus DSM 32788 (ST30) 28 days	qPCR method was used for the identification and quantification of gut microbiota. Pre-post Δ in Log10 cells/g Lactobacillus: Int: ↑ 0.2, Pla: ↑ 0.5, ^NS Bifidobacterium: Int: ↓ 0.2, Pla: ↑ 0.3 “Decreased in intervention group” (p < 0.05) Clostridium: Int: ↓ 1.0, Pla:↓ 1.0 ^NS Bacteroides: Int: ↓ 0.3, Pla: ↑ 0.1 ^NS
Lin et al. (78)	n = 21	Probiotic vs. placebo	Bifidobacterium longum subsp. Longum, 5 wk	16S rRNA gene sequencing Phylum: Int: Actinobacteria and Firmicutes greater abundance post-supplementation, compared with Pla. (p-value not shown). Proteobacteria reduced abundance post-supplementation, compared with Pla. (p-value not shown). Genus: Int: ↑ Bifidobacterium compared with Pla (p = 0.0027). 9-fold ↑ in Lactobacillus count. Species: Bifidobacterium longum subsp. longum relative abundance Int: 0.95%; ↑ 8.63-fold (p = 0.0178). Pla: 0.11% ^NS in amounts of common strains
Sánchez Macarro et al. (80)	n = 43 RCT		Bifidobacterium longum CECT 7347 Lactobacillus casei CECT 9104, and Lactobacillus rhamnosus CECT 8361 6 wk	16S rRNA gene sequencing Bacterial diversity Richness: Int:↔ 0, Pla: ↓6 ^NS Simpson index: Int: ↔ 0, Pla: ↑0.03, ^NS Shannon index: Int: ↑0.01, Pla: ↑0.15 ^NS Family (log relative counts) Rhodospirillaceae: Int < Pla, log2 fold = 2.71, p = 0.019 (adj) Streptococcaceae: Int < Pla, log2 fold = 2.20, p = 0.019(adj) Genera (log relative counts) Rhodospirillum: Pla > Int, p = 0.007(adj) Streptococcus: Pla > Int, p = 0.007(adj) Within group differences noted in genera.
Son et al. (84)	n = 15 RCT	Probiotic vs. placebo	L. acidophilus, L. casei, L. helveticus, B. bifidum, 60 days	16S rRNA gene sequencing Shannon and Simpson index ^NS in α-diversity, pre and post Species: ^NS changes in the abundance of the four microorganisms present (three Lactobacilli and one Bifidobacterium).
West et al. (90)	n = 88 RCT	Probiotic vs. placebo	Lactobacillus fermentum VRI-003 PCC^®, 11 wk	Microbiome Diversity (16SrRNA) ^NS changes in bacterial diversity (data not shown) All data reported as raw bacterial counts—no statistical testing of between group changes. Total bacteria: Males: Int ↓ 0.5 × 10¹⁰, Pla Pre: ↓ 0.5 × 10¹⁰ Females: Int ↑ 0.7 × 10¹⁰, Pla ↓ 1.0 × 10¹⁰ C. coccoides: Males: Int ↓ 2.3 × 10⁸, Pla ↓ 3.4 × 10⁸ Females: Int ↔ 0, Pla ↓ 1.54 × 10⁹ E. coli: Males: Int ↑ 6.4 × 10⁵, Pla ↑ 6.8 × 10⁵ Females: Int ↑ 1.36 × 10⁷, Pla ↑ 4.3 × 10⁴ Bifibacteria: Males: Int ↓ 0.3 × 10⁷, Pla ↓ 5.6 × 10⁶ Females: Int ↑ 0.7 × 10⁶, Pla ↓ 6.1 × 10⁶ Bacteroides: Males: Int ↑ 0.6 × 10⁶, Pla ↑ 1.6 × 10⁶ Females: Int ↑ 1.3 × 10⁶, Pla ↓ 4.4 × 10⁷ Lactobacillus: Males: Int ↑ 5.8 × 10⁴, Pla ↓ 2.8 × 10⁶ Females: Int ↑ 7.0 × 10⁴, Pla ↑ 6.9 × 10⁴
Coman et al. (92)	n = 10 RCT	Synbiotic vs. placebo	L. rhamnosus IMC 501[R], L. paracasei IMC 502[R], plus oat bran fiber, 4 wk	qPCR procedure for quantification of selected bacterial groups Log CFU/g feces Bacteroides-Prev.-Porphyr. spp.: Int ↓ 0.18 log CFU/g, Pla ↑ 0.21 log CFU/g ^NS Staphylococcus spp.: Int ↓ 0.08 log CFU/g, Pla ↑ 0.16 log CFU/g ^NS Cl. coccoides-Eubact. rectale group: Int: ↓ 0.33 log CFU/g, Pla ↓ 0.01 log CFU/g ^NS Lactobacillus spp.: Int: ↑ 1.44 log CFU/g (p < 0.05), Pla ↓ 0.43 log CFU/g ^NS Bifidobacterium spp.: Int: ↑ 1.52 log CFU/g (p < 0.05), Pla ↑ 0.16 log CFU/g ^NS Enterobacteriaceae: Int: ↓ 0.14 log CFU/g, Pla ↑ 0.35 log CFU/g ^NS
Valle et al. (96)	n = 65 RCT	Synbiotic vs. placebo	Lactobacillus acidophilus LA-5; Bifidobacterium animalis BB-12 2.3 g of inulin, 30 days	16S gene sequencing α–Diversity (Shannon index): Int:↓ 0.125 Pla: ↑0.027 ^NS α–Diversity (Simpson index): Int: ↓0.017, Pla: ↑0.01 ^NS
West et al. (98)	n = 22 RCT	Synbiotic vs. prebiotic	L. paracasei subs Paracasei (L. casei 431^®), B. animalis ssp lactis (BB-12^®), L. acidophilus LA-5, L. rhamnosus GG, Raftiline, Raftilose GR, 3 wk	Microbiome Diversity (16SrRNA) ^NS changes in bacterial diversity (data not shown) All data reported as raw bacterial counts. Total bacteria: Syn ↔ 0, ^NS, Pre ↑ 2 × 10⁸ Total Lactobacillus (mean): Syn ↔ 0, Pre ↑ 1.5 × 10⁴ ^NS L. paracasei (mean): Syn ↑ 8 × 10², Pre ↓ 2 × 10² (“large” 9-fold difference) B. lactis (mean): Syn ↑ 2.7 × 10⁴, Pre ↑ 4.8 × 10^3NS
Short chain fatty acids
Damen et al. (55)	n = 27 RXT	Prebiotic vs. placebo	Arabinoxylan oligosaccharides (AXOS), 3 wk	All data reported in μmol/g wet feces Total SCFA: Int: ↑ 25.3 (p < 0.05), Pla ↑ 9.6 ^NS Acetic acid: Int: ↑ 10.2, Pla ↑ 4.8^NS Butyric acid: Int: ↑ 7.6 (p < 0.05), Pla ↑ 2.3^NS Propionic acid: Int: ↑ 3.2, Pla ↑ 1.3^NS
Finegold et al. (56)	n = 32 RCT	Prebiotic vs. Prebiotic vs. placebo	High and Low dose Xylooligosaccharides (XOS), 8 wk	Total SCFA (μmol/g dry feces): High ↓ 0.01, Low ↓ 0.06, Pla ↓ 0.06^NS
François et al. (57)	n = 63 RXT	Prebiotic vs. Prebiotic vs. placebo	Arabinoxylan oligosaccharides (AXOS), 3 wk	All data reported in μmol/g dry feces Total SCFA: High vs. Pla: ↑ 53.1 (p = 0.001), Low vs. Pla: ↑ 7.8 ^NS Acetic acid: High vs. Pla: ↑ 38.5 (p = 0.003), Low vs. Pla: ↑ 8.9 ^NS Butyric acid: High vs. Pla: ↑ 5.0 (p = 0.05), Low vs. Pla: ↓ 3.9 ^NS Propionic acid: High vs. Pla: ↑ 9.7 (p = 0.003), Low vs. Pla: ↑ 2.9 ^NS
Kleessen et al. (59)	n = 45 RCT	Prebiotic vs. prebiotic vs. placebo	Chicory inulin (CH) or Jerusalem artichoke inulin (JA), 3 wk	Total SCFA post-intervention (μmol/g wet feces): CH: 142.4, JA: 135.2, Pla: 138.8 ^NS
Reimer et al. (60)	n = 48 RXT	Prebiotic vs. Prebiotic vs. placebo	Chicory inulin type fructans (ITF), 4 wk	Fecal acetate Int 1: ↑ 2.9 umol/g, Con 1: ↑ 6.7 umol/g ^NS Int 2: ↑ 6.7 umol/g, Con 2: ↑ 9.2 umol/g ^NS Fecal proprionate Int 1: ↑ 3.8 umol/g, Con 1: ↑ 2.4 umol/g ^NS Int 2: ↓ 1.3 umol/g, Con 2: ↑ 1.3 umol/g ^NS Fecal butyrate Int 1: ↑ 2.5 umol/g, Con 1: ↑ 0.3 umol/g ^NS Int 2: ↑ 4.4 umol/g, Con 2: ↑ 6.7 umol/g ^NS Fecal Isobutyrate Int 1: ↔ 0 umol/g, Con 1: ↑ 0.6 umol/g ^NS Int 2: ↔ 0 umol/g, Con 2: ↔ 0 umol/g ^NS Fecal Isovalerate Int 1: ↔ 0 umol/g, Con 1: ↔ 0 umol/g ^NS Int 2: ↔ 0 umol/g, Con 2: ↑ 0.4 umol/g ^NS
Huang et al. (74)	n = 20 male RCT	Probiotic vs. placebo	L. plantarum PS128, 4 wk	Acetic acid (mean, post only): Int: 4.7 ng/ml, Pla: 3.8 ng/ml Int > Pla (p < 0.05) Proprionic acid (mean, post only): Int: 1.18 ng/ml, Pla: 0.5 ng/ml Int > Pla (p < 0.05) Butyric acid (mean, post only): Int: 0.5 ng/ml, Pla: 0.3 ng/ml Int > Pla (p < 0.05) Decanoic acid (mean, post only): Int: 0.005 ng/ml, Pla: 0.002 ng/ml ^NS Heptanoic acid (mean, post only): Int: 0.6 ug/ml, Pla: 0.4 ug/ml ^NS Hexanoic acid (mean, post only): Int: 1.7 ug/ml, Pla: 4.0 ug/ml ^NS Isobutyric acid (mean, post only): Int: 0.050 ng/ml, Pla: 0.052 ng/ml ^NS Isovaleric acid (mean, post only): Int: 0.03 ng/ml, Pla: 0.04 ng/ml ^NS Octanoic acid (mean, post only): Int: 1.1 ug/ml, Pla: 0.7 ug/ml ^NS Valeric acid (mean, post only): Int: 0.07 ng/ml, Pla: 0.07 ng/ml ^NS
Son et al. (84)	n = 15 RCT	Probiotic vs. placebo	L. acidophilus, L. casei, L. helveticus, B. bifidum, 60 days	Acetic acid Int: ↓ 40 umol/g, Pla: ↓ 85 umol/g ^NS Buytric acid Int: ↓ 142 umol/g, Pla: ↑ 125 umol/g Int > Pla at baseline (p-value not shown) Propionic acid Int: ↓ 1.31 umol/g, Pla: ↓ 1.51 umol/g ^NS
Klein et al. (75)	n = 26 RXT	Probiotic vs. placebo	B. lactis 420 × , L. acidophilus 74-2, 5 wk	All data post-intervention concentration (μmol/g feces) Total SCFAs: Int 85.0 μmol/g, Pla 88.5 μmol/g ^NS Acetic acid Int: 46.7 μmol/g, Pla 49.5 μmol/g ^NS i-Butyric acid Int 1.9 μmol/g, Pla 2.0 μmol/g ^NS n-Butyric acid Int 14.6 μmol/g, Pla 15.1 μmol/g ^NS Propionic acid Int: 16.7 μmol/g, Pla 16.9 μmol/g ^NS Valeric acid: Int: 2.1 μmol/g, Pla 2.0 μmol/g ^NS Isovaleric acid: Int: 2.3 μmol/g, Pla 2.4 μmol/g ^NS Caproic acid: Int: 0.7 μmol/g, Pla 0.6 μmol/g ^NS
Valle et al. (96)	n = 65	Synbiotic vs. placebo	Lactobacillus acidophilus LA-5; Bifidobacterium animalis BB-12 2.3 g of inulin, 30 days	Fecal acetate (mmol/L): Int: OR 0.34, 95%CI −0.06, 0.74 Pla: OR 0.16, 95%CI −0.25, 0.57 ^NS between groups
				Fecal proprionate (mmol/L): Int: OR 0.20, 95%CI −0.01, 0.41 Pla: OR 0·31, 95%CI −0.02, 0.63 ^NS between groups Fecal butyrate (mmol/L): Int: OR 0.39, 95%CI 0.20, 0.59 Pla: OR 0.25, 95%CI −0.03, 0.47 ^NS between groups Fecal ammonia (mmol/l): Pla: OR 0.09, 95%CI 0.01, 0.17 Int: OR 0.11, 95%CI 0.04, 0.18 ^NS between groups
West et al. (98)	n = 22 RCT	Synbiotic vs. prebiotic	L. paracasei subs Paracasei (L. casei 431^®), B. animalis ssp. lactis (BB-12^®), L. acidophilus LA-5, L. rhamnosus GG, Raftiline, Raftilose GR, 3 wk	All data reported in μmol/g feces Acetic acid: Syn ↓ 2, Pre ↓ 6 ^NS Butyric acid: Syn ↓ 2, Pre ↓ 3 ^NS Propionic acid: Syn ↓ 2, Pre ↓ 1.5 ^NS
Gastrointestinal symptoms
Damen et al. (55)	n = 27 RXT	Prebiotic vs. placebo	Arabinoxylan oligosaccharides (AXOS), 3 wk	GIS: Insufficient incidence to analyze abdominal pain or bloating. Flatulence: Int: ^NS difference pre-to-post Pla: ↑ 0.53 on 0–4 scale pre-to-post (P = 0.02)
Finegold et al. (56)	n = 32 RCT	Prebiotic vs. Prebiotic vs. placebo	Xylooligosaccharides (XOS), 8 wk	Symptoms rated from 0 (no symptoms) to 3 (severe) Excess flatus: High ↑ 0.27, Low ↑ 0.26, ↑ Pla 0.19 ^NS Borborygmi: High ↑ 0.26, Low ↑ 0.11, ↑ Pla 0.02 ^NS Bloating: High ↑ 0.28, Low ↑ 0.22, ↑ Pla 0.06 ^NS Abdominal pain: High ↓ 0.01, Low ↑ 0.27, ↑ Pla 0.10 ^NS
François et al. (57)	n = 63 RXT	Prebiotic vs. Prebiotic vs. placebo	Arabinoxylan oligosaccharides (AXOS), 3 wk	↑ Occurrence frequency + ↑ Distress severity, flatulence only cf Pla (P = 0·02) Flatulence (mild/moderate/very disturbing symptoms, %): High 27/7/2, Low 16/7/2, Pla 11/6/2 ^NS ^NS all other symptoms.
Kleessen et al. (59)	n = 45 RCT	Prebiotic vs. prebiotic vs. placebo	Chicory inulin (CH) or Jerusalem artichoke inulin (JA), 3 wk	All data reported as incidence (%) post-supplementation Flatulence: CH 87, JA 93, Pla 47 (CH and JA > Pla, p < 0.05) Abdominal bloating: CH: 0, JA: 27, Pla: 27 ^NS Abdominal pain or cramps: CH: 20, JA: 7, Pla: 7 ^NS Bowel Rumbling: CH: 13, JA: 13, Pla: 13 ^NS Bowel Cramps: CH: 20, JA: 20, Pla: 13 ^NS
Reimer et al. (60)	n = 48 RXT	Prebiotic vs. Prebiotic vs. placebo	Chicory inulin type fructans (ITF), 4 wk	Abdominal pain, 0–4 Int 1: 0.3 ± 0.2, Con 1: 0.3 ± 0.2 ^NS Int 2: 0.4 ± 0.2, Con 2: 0.3 ± 0.2 ^NS Distension/bloating (0–4) Int 1: 0.5 ± 0.3, Con 1: 0.4 ± 0.2 (P = 0.025) Int 2: 0.6 ± 0.2 (P = 0.023), Con 2: 0.2 ± 0.1 (P = 0.048) ^NS between groups Flatulence (0–4) Int 1: 0.3 ± 0.2, Con 1: 0.3 ± 0.2 ^NS Int 2: 0.3 ± 0.2, Con 2: 0.0 ± 0.2 ^NS Stomach rumbling (0–4) Int 1: 0.1 ± 0.2, Con 1: 0.1 ± 0.2 ^NS Int 2: 0.2 ± 0.2, Con 2: 0.1 ± 0.1 ^NS
Russo et al. (45)	n = 20 RXT	Prebiotic vs. placebo	Inulin-enriched pasta, 5 wk	^NSDifferences and no major symptoms (data not reported)
Gleeson et al. (70)	n = 58 RCT	Probiotic vs. placebo	L. casei Shirota, 16 wk	GIS Incidence: Int 54%, Pla 57% ^NS Proportion of days with GIS: Int 2%, Pla 3% (p = 0.008)
				Severity Score: Int 9, Placebo 12 ^NS Symptom duration (days): Int 4.2, Pla 5.9 ^NS
Haywood et al. (72)	n = 30 RCT	Probiotic vs. placebo	L. gasseri, B. bifidum, B. longum, 4 wk	GIS Incidence: Int: 13%, Pla: 13% ^NS
Pugh et al. (79)	n = 24	Probiotic vs. placebo	L. acidophilus CUL60, L. acidophilus CUL21, B. bifidum CUL20, B. animalis subsp. Lactis CUL34, 4 wk	Number of GI scores ≥ 4: Days 1–14: Int 4, Pla 5^NS Days 15–28: Int 2, Pla 11 ^NS
Schreiber et al. (82)	n = 27 RCT	Probiotic vs. placebo	L. helveticus Lafti L10, B. animalis ssp. lactis Lafti B94 E. faecium R0026, B. longum R0175 Bacillus subtilis R0179, 90 days	GIS incidence at rest (ΔGI): Int: −30 ± 48%, Pla: −27 ± 47% ^NS Categorized as: Nausea incidence at rest (ΔGI): Int −16 ± 43%, Pla: 71 ± 119% Int < Pla, P = 0.01, d = 0.9 Belching incidence at rest (ΔGI): Int: −14 ± 53%, Pla: 62 ± 115%, Int < Pla, P = 0.04, d = 1 Vomiting incidence at rest (ΔGI): Int: −7 ± 30%, Pla: 49 ± 114%, Int < Pla, P = 0.04, d = 0.7 Other sub-categories not reported.
Strasser et al. (85)	n = 29 RCT	Probiotic vs. placebo	Bifidobacterium bifidum W23 Bifidobacterium lactis W51 Enterococcus faecium W54 Lactobacillus acidophilus W22 Lactobacillus brevis W63 Lactococcus lactis W58 12 wk	Incidence: “Only one participant in the placebo group experienced GI-discomfort symptoms during the study period.”
West et al. (90)	n = 88 RCT	Probiotic vs. placebo	Lactobacillus fermentum VRI-003 PCC^®, 11 wk	No. of GIS episodes: Male: Int 1.01, Pla: 0.49 (Likely ↑) Female: Int 1.44, Pla 0.48, (Likely ↑) Duration of GIS episodes (days): Male: Int 3.3, Pla 1.3, (Likely ↑) Female: Int 3.9, Pla 2.1, (Possible ↑) GIS severity (1–3 scale): Male: Int 1.31, Pla 1.78 (Possible ↓) Female: Int 1.44, Pla 1.75 (Possible ↓) Symptom Load (severity-days): Male: Int 4.4, Pla 2.5 (Possible ↑) Female: Int 5.2, Pla 2.9 (Possible ↑)
Coman et al. (92)	n = 10 RCT	Synbiotic vs. placebo	L. rhamnosus IMC 501[R], L. paracasei IMC 502[R], oat bran fiber, 4 wk	Data reported as change from baseline, Likert scale (0–5) Intestinal regularity: Int ↑ 2.6, Pla ↑ 1.8 (p < 0.05) Stool volume: Int ↑ 1.8, Pla ↑ 2.2^NS Ease at defecation: Int ↑ 2.2, Pla ↑ 0.6 (p < 0.05) Bloating: Int ↑ 0.2, Pla ↑ 0.4^NS Abdominal pain: Int ↔ 0.0, Pla ↓ 0.2^NS Intestinal cramps: Int ↔ 0.0, Pla ↓ 0.4^NS
Roberts et al. (94)	n = 20 RCT	Synbiotic vs. placebo	L. acidophilus CUL-60 (NCIMB 30157), L. acidophillus CUL-21 (NCIMB 30156), B. bifidum CUL-20, B. animalis subspecies lactis CUL-34 (NCIMB 30153), Fructooligosaccharides, 12 wk	Mean total GIS score during supplemental period: Int 7.00, Pla 13.9 (p < 0.001) Mean GIS severity score during supplemental period: Int 8.00, Pla 16.7 (p < 0.001)
Valle et al. (96)	n = 65	Synbiotic vs. placebo	Lactobacillus acidophilus LA-5; Bifidobacterium animalis BB-12 2·3 g of inulin, 30 days	Sum of symptoms (nausea, vomiting, diarrhea, abdominal pain, flatulence, loss of appetite, burning and dysphagia) Int: Δ Post-supp.: OR −2·24, 95%CI −3·15, −1·34 Pla: Δ Post-supp: OR −1·16, 95%CI −2·51, 0·18 ^NSBetween groups.

CFU, colony forming units; CRP, c-reactive protein; FISH, fluorescence in situ hybridization; GIS, Gastrointestinal symptoms; IFN, interferon; IL, interleukin; Int, Intervention; LBP, lipopolysaccharide binding protein; LPS, lipopolysaccharide; NS, Not significant; OTU, operational taxonomy units; Pla, Placebo; Pre, Prebiotic intervention; RCT, Randomized control trial; RXT, Randomized crossover trial; Syn, Synbiotic intervention; wk, weeks.