Dietary Fiber and FODMAP-Restricted Diet in IBS
Dietary Fiber and FODMAP-Restricted Diet in IBS
In 2005, Rees et al. conducted a longitudinal, prospective, randomised, placebo-controlled trial in England, in patients with IBS-C meeting Rome I criteria. Patients were included if stool frequency was reported to be less than once per day or was of variable frequency, if their stools were once or twice a day and 'hard', 'pellety' or 'variable' in form, or if straining to defecate was common. Twenty-eight patients (86% female) with a mean age of 36 years (range 20–69 years) were recruited, and 14 each were randomised to a fibre intervention or placebo. The fibre intervention was 10–20 g/day of coarse wheat bran supplement to their normal diet vs. a low fibre placebo for 8–12 weeks. All stools were collected for a 7-day baseline period, to allow assessment of whole gut transit time using radio-opaque markers (hours), frequency of defecation (number/day), faecal wet weight (g/24 h) and faecal form (scale 1–8; 1 = watery, 8 = pellety). After 8–12 weeks of intervention, reassessment of these parameters was done. They found that the fibre intervention group had an increase in faecal wet weight (g/24 h) of 28 ± 25 g compared with the placebo group, which demonstrated a mean decrease of 10 ± 41 g (P < 0.02). Other bowel function measurements and recorded symptoms did not differ significantly.
In 2011, Choi et al. conducted a RCT in South Korea, in patients with IBS meeting Rome III criteria, who were subtyped into IBS-C, IBS-D (diarrhoea predominant) and IBS-M (mixed). A total of 142 patients (75% female with a mean age of 33.9 years) were recruited, and 70 were randomised to the fibre intervention for 4 weeks. The fibre intervention was 150 mL of probiotic fermented milk with 3.15 g fibre powder using sea tangle extract, radish extract and glasswort extract, which are mostly soluble fibres, vs. 150 mL probiotic fermented milk alone. Changes in Visual Analog Scale (VAS) scores were measured for abdominal pain or discomfort, abdominal distention or bloating, urgency, straining, feeling of incomplete evacuation and improvement in overall IBS symptoms, in addition to flatulence/week, frequency/week, defecation duration and BSFS for stool consistency. For the overall IBS group, all parameters improved in both groups except for flatulence, defecation frequency, stool consistency and feeling of incomplete evacuation. Straining improved more in the fibre group. Similar trends were seen for the other IBS subtypes, however, in the IBS-C group defecation frequency was significantly improved in the fibre group (Δ3.97 BMs/week, P = 0.007), and was not significantly improved in the control (Δ0.53 BMs/week, P = 0.53). Based on their results the probiotic fermented milk improved numerous parameters in IBS, with an additive benefit of increased stool frequency conferred by fibre supplementation in the IBS-C group.
In 2012, Min et al. conducted a RCT in South Korea, in patients with IBS meeting Rome III criteria. One hundred and thirty patients (70% female) with a mean age of 35.8 years were recruited, and 65 each were randomised to the fibre intervention or placebo for 8 weeks. The fibre intervention was twice daily composite yoghurt with acacia dietary fibre, high-dose B. lactis vs. a control product. The subgroup of IBS-C had a total of 19 patients in the treatment group and 22 in the control arm. In IBS-C, improvement in overall IBS symptoms was significantly higher in the test group than in the control group (72.4 ± 18.4 vs. 50.0 ± 21.8, P < 0.001). The bowel habit satisfaction did not differ between the test and control groups, and while defecation frequency and feeling of incomplete evacuation did differ between the groups, it improved in both groups.
In 2012, Cockerell et al. conducted an open randomised controlled trial in England, in patients with IBS meeting Rome III criteria. Forty patients (53% female) were recruited, aged 18–70 years, and 13 each were randomised to two separate treatment arms, and 13 were randomised to no therapy. The fibre interventions included two tablespoons twice daily of whole linseeds and two tablespoons twice daily of ground linseeds vs. no therapy. Thirty-one subjects completed the study. The primary outcome measure was a reduction in symptom severity score from the baseline week to week 4. The authors found in a per protocol analysis that subjects in the intervention groups reported a significant improvement in composite symptom severity scores from baseline to week 4 in whole linseeds vs. control [299.7 (94) vs. 215.7 (147); P = 0.017] and ground linseeds vs. control (310.6 (140) vs. 246.3 (154); P = 0.006)]. However, no significant difference was found in the number of subjects who improved between any of the groups in the intention-to-treat analysis [whole linseeds n = 8/14 (57%); ground linseeds n = 10/13 (77%); controls n = 5/13 (39%); P = 0.140].
Fibre and Irritable Bowel Syndrome (Table 2)
In 2005, Rees et al. conducted a longitudinal, prospective, randomised, placebo-controlled trial in England, in patients with IBS-C meeting Rome I criteria. Patients were included if stool frequency was reported to be less than once per day or was of variable frequency, if their stools were once or twice a day and 'hard', 'pellety' or 'variable' in form, or if straining to defecate was common. Twenty-eight patients (86% female) with a mean age of 36 years (range 20–69 years) were recruited, and 14 each were randomised to a fibre intervention or placebo. The fibre intervention was 10–20 g/day of coarse wheat bran supplement to their normal diet vs. a low fibre placebo for 8–12 weeks. All stools were collected for a 7-day baseline period, to allow assessment of whole gut transit time using radio-opaque markers (hours), frequency of defecation (number/day), faecal wet weight (g/24 h) and faecal form (scale 1–8; 1 = watery, 8 = pellety). After 8–12 weeks of intervention, reassessment of these parameters was done. They found that the fibre intervention group had an increase in faecal wet weight (g/24 h) of 28 ± 25 g compared with the placebo group, which demonstrated a mean decrease of 10 ± 41 g (P < 0.02). Other bowel function measurements and recorded symptoms did not differ significantly.
In 2011, Choi et al. conducted a RCT in South Korea, in patients with IBS meeting Rome III criteria, who were subtyped into IBS-C, IBS-D (diarrhoea predominant) and IBS-M (mixed). A total of 142 patients (75% female with a mean age of 33.9 years) were recruited, and 70 were randomised to the fibre intervention for 4 weeks. The fibre intervention was 150 mL of probiotic fermented milk with 3.15 g fibre powder using sea tangle extract, radish extract and glasswort extract, which are mostly soluble fibres, vs. 150 mL probiotic fermented milk alone. Changes in Visual Analog Scale (VAS) scores were measured for abdominal pain or discomfort, abdominal distention or bloating, urgency, straining, feeling of incomplete evacuation and improvement in overall IBS symptoms, in addition to flatulence/week, frequency/week, defecation duration and BSFS for stool consistency. For the overall IBS group, all parameters improved in both groups except for flatulence, defecation frequency, stool consistency and feeling of incomplete evacuation. Straining improved more in the fibre group. Similar trends were seen for the other IBS subtypes, however, in the IBS-C group defecation frequency was significantly improved in the fibre group (Δ3.97 BMs/week, P = 0.007), and was not significantly improved in the control (Δ0.53 BMs/week, P = 0.53). Based on their results the probiotic fermented milk improved numerous parameters in IBS, with an additive benefit of increased stool frequency conferred by fibre supplementation in the IBS-C group.
In 2012, Min et al. conducted a RCT in South Korea, in patients with IBS meeting Rome III criteria. One hundred and thirty patients (70% female) with a mean age of 35.8 years were recruited, and 65 each were randomised to the fibre intervention or placebo for 8 weeks. The fibre intervention was twice daily composite yoghurt with acacia dietary fibre, high-dose B. lactis vs. a control product. The subgroup of IBS-C had a total of 19 patients in the treatment group and 22 in the control arm. In IBS-C, improvement in overall IBS symptoms was significantly higher in the test group than in the control group (72.4 ± 18.4 vs. 50.0 ± 21.8, P < 0.001). The bowel habit satisfaction did not differ between the test and control groups, and while defecation frequency and feeling of incomplete evacuation did differ between the groups, it improved in both groups.
In 2012, Cockerell et al. conducted an open randomised controlled trial in England, in patients with IBS meeting Rome III criteria. Forty patients (53% female) were recruited, aged 18–70 years, and 13 each were randomised to two separate treatment arms, and 13 were randomised to no therapy. The fibre interventions included two tablespoons twice daily of whole linseeds and two tablespoons twice daily of ground linseeds vs. no therapy. Thirty-one subjects completed the study. The primary outcome measure was a reduction in symptom severity score from the baseline week to week 4. The authors found in a per protocol analysis that subjects in the intervention groups reported a significant improvement in composite symptom severity scores from baseline to week 4 in whole linseeds vs. control [299.7 (94) vs. 215.7 (147); P = 0.017] and ground linseeds vs. control (310.6 (140) vs. 246.3 (154); P = 0.006)]. However, no significant difference was found in the number of subjects who improved between any of the groups in the intention-to-treat analysis [whole linseeds n = 8/14 (57%); ground linseeds n = 10/13 (77%); controls n = 5/13 (39%); P = 0.140].