(i) 4-week washout period between each arm (ii) Analysis 0–2 weeks only in both groups (iii) Analysis at week 3 was taken the day after prebiotic was ceased (iv) Increased bifidobacterium levels at 2 weeks, ; compared to placebo, this was lost at week 3 (v) Correlation pre- and postintervention bifidobacterium levels = −0.51 (vi) Usual diet, asked to have a regular eating pattern (3 meals/day), and foods containing prebiotics were limited to 1/week
S1: lactulose 20 g S2: OF-IN (Orafti Synergy1) (i) Oligofructose degree of polymerization = 4, 10 g (ii) Raftiline HP degree of polymerization = 25, (2,1) linkage, 10 g 2 dose/day
(i) Both studies increased in bifidobacterium levels S1: , S2: , and no difference between studies (ii) Correlation between baseline PC levels and effect of prebiotic intervention ( = −0.64) (S1), = −0.74 (S2) ) (iii) No runout period (iv) Usual diet, advised to keep stable. Avoid fermented milk products and foods containing fermentable carbohydrates
(i) Post was measured on the 6th day of ingestion (ii) Increased bifidobacterium levels and lactobacillus and , respectively. Decrease in bacteroidaceae < 0.05 (iii) 6 day runout levels PC, indole returned towards baseline (iv) Usual diet with no lactose containing foods or fermentation products
(i) Post was measured on 6th day of week 3 (ii) Participants were selected out of a group of 28 on the basis of the lowest bifidobacterium levels (iii) Increased bifidobacterium levels < 0.05 (iv) 6 day runout levels indole decreased further 23.4 mg/L (v) Usual diet with no lactose containing foods or fermentation products
(i) Increased bifidobacterium levels and lactobacillus < 0.001 and < 0.05, respectively. Decrease in bacteroidaceae < 0.05 (ii) Usual diet. Avoided food with abundant viable cultures (iii) 1 week runout period levels returned to preintervention levels*
Inulin degree of polymerization = 12, (2,1) linkage 15 g 3 dose/day
0–4 wks
Heat and acid deproteinisation, GCMS
Δ Urinary PC (mg/24 hr) ∧ (wk 0–4) Total: 32.3–22.3 (−10) ns Percentage of isotope (2H4p-cresol): 0.81–0.51 (−0.3 ) ns
(i) Low overall recovery of the label (ii) 1 week runout urinary PC and urinary percentage of isotope increased towards baseline. Fecal PC exceeded baseline, 13.33 mg/72 hrs, and fecal percentage of isotope decreased further to 0.44%
Very low PC−
Outcome markers-total PC and stable isotopes [2]p-cresol given as [2]tyrosine in test meal
Δ Fecal PC (mg/72 hr) ∧ (wk 0–4) Total: 9.7–9.3 (−0.4) ns Percentage of isotope (2H4p-cresol): 0.78–0.71 (−0.07) ns
(iii) Usual diet, advised to keep constant macronutrient composition. Diet records kept at intervals throughout the study to allow for qualitative comparison—results not reported