Dietary fibre

A candidate probiotic with unfavourable effects in subjects with irritable bowel syndrome: a randomised controlled trial

BACKGROUND

Some probiotics have shown efficacy for patients with irritable bowel syndrome (IBS). Lactobacillus (L.) plantarum MF1298 was found to have the best in vitro probiotic properties of 22 strains of lactobacilli. The aim of this study was to investigate the symptomatic effect of L. plantarum MF1298 in subjects with IBS. Primary outcome was treatment preference and secondary outcomes were number of weeks with satisfactory relief of symptoms and IBS sum score.

METHODS

The design was a randomised double blind placebo-controlled crossover trial. 16 subjects with IBS underwent two three-week periods of daily intake of one capsule of 10(10) CFU L. plantarum MF 1298 or placebo separated by a four-week washout period.

RESULTS

Thirteen participants (81%; 95% CI 57% to 93%; P = 0.012) preferred placebo to L. plantarum MF1298 treatment. The mean (SD) number of weeks with satisfactory relief of symptoms in the periods with L. plantarum MF1298 and placebo were 0.50 (0.89) and 1.44 (1.26), respectively (P = 0.006). IBS sum score was 6.44 (1.81) in the period with L. plantarum MF1298 treatment compared with 5.35 (1.77) in the period with placebo (P = 0.010). With a clinically significant difference in the IBS sum score of 2 in disfavour of active treatment, the number needed to harm was 3.7, 95% CI 2.3 to 10.9.

CONCLUSIONS

This trial shows for the first time an unfavourable effect on symptoms in subjects with IBS after intake of a potential probiotic.

Effect of bran, ispaghula, and inert plastic particles on gastric emptying and small bowel transit in humans: the role of physical factors

BACKGROUND

Coarse bran is known to accelerate transit through the whole gut and to increase stool weight. This effect is much reduced by grinding the bran, suggesting that particle size influences gut motor patterns.

AIMS

To compare the effect of 15 g coarse bran with 15 g inert plastic particles and 7 g of ispaghula on the gastric emptying and small bowel transit of a rice pudding test meal.

SUBJECTS

13 healthy volunteers.

METHODS

Transit of 99mTc labelled rice studied by gamma-scintigraphy measuring gastric emptying and colonic arrival over 10 hours. Small bowel transit was estimated from the difference between time to 50% gastric emptying and 50% colonic arrival.

RESULTS

Bran delayed gastric emptying by 22 (SEM 8) minutes compared with control values of 88 (SEM 6) minutes p < 0.05. Ispaghula and plastic particles had no significant effect. Small bowel transit was accelerated compared with control values of 322 (SEM 29) minutes, decreasing by 95 (29) minutes and 62 (22) minutes after bran and plastic particles respectively. Ispaghula again showed no significant effect.

CONCLUSION

Coarse bran delays gastric emptying and accelerates small bowel transit. The marked acceleration of small bowel transit also seen with inert plastic particles may be due to increased upper gut secretions after stimulation of enteric nerves.

Bran supplementation in the treatment of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome remains the commonest reason for referral to a gastroenterology clinic. Patients with irritable bowel syndrome are frequently advised to increase their intake of bran fibre, despite inconclusive experimental evidence of benefit.

METHODS

The effect of dietary supplementation with a bolus of bran fibre (12 g/day) was studied in a block-randomized, placebo-controlled, crossover study of 80 patients with irritable bowel syndrome referred to a District General Hospital outpatient clinic. Comparison of the benefits of bran and placebo was based upon personal assessment of individual and overall symptom profiles, determined from a simple daily symptom score and post-treatment interview.

RESULTS

Overall symptomatic improvement was reported with bran by 52% and with placebo by 54% of patients. Bran supplementation was no more effective than placebo in improving individual symptoms of irritable bowel syndrome, and for wind-related symptoms it was significantly less effective (P < 0.001).

CONCLUSION

Dietary supplementation with bran is of no value in the treatment of patients with irritable bowel syndrome referred to a hospital clinic.

Pharmacology of dietary fibre

"Dietary fibre" includes a range of relatively poorly digested food substances mainly composed of non-starch polysaccharides. Pectins and gums are multi-branched hydrophilic substances, forming viscous solutions that delay gastric emptying and nutrient absorption from the small bowel. They are used to delay gastric emptying and improve glycemic control in diabetes, as well as to alleviate constipation. Other fibres, including cellulose and lignins, are insoluble and have little effect on gastric emptying and small bowel transit. They markedly accelerate colonic transit and are frequently used as laxatives. Other important, less well-characterised effects of fibre include lowering of blood cholesterol, increase in satiety and possibly reduction in colon neoplasia.

Design for the elderly: a biological perspective

In past times growing old has been synonymous with increasing disability, so that the old have been seen as sans everything. But it is argued here that old age no longer needs to be a time of greater disability, especially if the lifestyles of children and adults are made as healthy as those in less industrialized nations. Design for old age should consder the effects of ageing tissues and common chronic diseases, but, more importantly, should empower the elderly person so that they may continue a dignified, productive life.