Table 3

Six key strategies that might underpin personalised fibre therapy in the future, including their rationale and tips

StrategyRationaleTips
Assess clinical phenotypeCurrently routinely performed as part of clinical assessment – enables definition of targeted symptoms.Care needs to be exercised in defining the characteristics of the bowel habit as terminology as understood by the patient may be different to that of the clinician.74
Assess background fibre intake and dietary pattern

  • Differences in background intake can impact:

    • Response to fibre intervention.102

    • Likelihood of adverse effects.

    • Amount able to be used.

  • Excessive total fibre intake (background and supplemental) may not be tolerable.

    • No evidence of acute clinical benefits in IBS.

  • Irregular eating (eg, missing meals) in patients can compromise the capacity of patients to meet fibre intake requirements.

  • Low (below typically recommended intake of <25 g/day)93:

    • Focus is more on increasing total fibre intake than inducing subtle changes by optimising fibre types consumed.

  • High (≥25 g/day)93:

    • Manipulating the fibre types consumed may offer more clinical value.

  • Encourage regular meal pattern:

    • More regular meals will enable fibres (and other bioactive compounds) to be consumed in smaller doses throughout the day while promoting greater variety of foods (and fibres) consumed.

    • Influence timing of the supplements (eg, splitting fibre dose across the day).

Define the GI physiologyThere is substantial heterogeneity in physiology in the IBS population with regard to:

  • Stool characteristics (including output).

  • Regional transit time.

  • Microbiota characteristics, such as

    • Rate, type and localisation of fermentation.

    • Activity of small intestinal bacterial population (eg, ‘small intestinal bacteria overgrowth’).

Methodologies for defining these aspects might include:

  • Assessment of faecal output and characteristics.

  • Breath hydrogen/methane testing.

  • Wireless motility capsule to evaluate transit and regional colonic pH.

  • Gas-sensing capsule (experimental) to evaluate transit and regional hydrogen concentration.103

  • Microbiota composition and metabolic output.


The value of these data are limited by precision, cost, availability, feasibility and availability of existing values for their interpretation.
Tailor fibre type to desired effectDifferent fibre types and combinations have different physiological effects within the colon (see table 2).Based on clinical phenotype, examples include:

  • Patient presenting with moderate abdominal pain, firm bowel movements, prolonged GI transit and low background fibre intake:

    • Initiating patient on the low FODMAP diet with adjunctive supplementation of a fibre combination (minimally fermented and bulking and slowly fermented (see table 1 and figure 3)).

  • Patient presenting with severe abdominal pain, loose bowel movements, rapid GI transit time and high background fibre intake:

    • Initiating patient on the low FODMAP diet with adjunctive supplementation of minimally fermented, viscous fibre.

  • Patient presenting with mild abdominal pain, normal bowel movements, regular GI transit and moderate background fibre intake:

    • Introducing supplementation of a slowly fermented fibre as a monotherapy.

Titrate fibre dose to enhance tolerabilityGiven the heightened sense of visceral sensitivity in many patients with IBS, the changes in colonic volume in response to fibre therapy, regardless of functional characteristics, may induce GI symptoms if introduced too quickly.When commencing fibre therapy:

  • Start at 25% of target dose.

  • Up-titrate the dose over several days, according to individual tolerance, until the target dose is reached.

Objectively assess response to the fibre interventionEffect of fibre choice, dose and/or combination can be monitored using physiological indices with appropriate tailoring of therapy.No such methodologies exist to objectively evaluate the success of such therapeutic tailoring. The lack of quality evidence available limits the use and interpretation of methodologies described previously.
Responses to fibre currently assessed by subjective changes in symptoms and bowel habit.

  • FODMAPs, fermentable oligosaccharides, disaccharides, monosaccharides and polyols.