Combinations of dietary fibres can be used as a strategy to engineer synergistic health-promoting metabolite responses in an individual, while establishing a standardised framework for describing fermentation rates across studies.
Key Findings
Results
A blend of sugarcane fibre and cassava resistant starch produced significantly higher butyrate levels than either fibre alone.
The combination produced significantly higher butyrate levels (p < 0.0001) than either fibre tested individually.
This synergistic effect was observed in an n-of-1 longitudinal study design using fresh individual faecal material rather than pooled samples.
The finding suggests that fibre combinations can be strategically selected to engineer specific metabolite outcomes beyond what individual fibres can achieve.
Results
Inulin and pectin selectively enriched Bifidobacterium spp. in microbial profiling.
Microbial profiling was conducted as part of an n-of-1 longitudinal study examining responses to eight distinct dietary fibres.
Fibres were fermented both individually and in combination to assess differential microbial responses.
The selective enrichment of Bifidobacterium spp. by inulin and pectin was identified through temporal microbial composition analysis.
Results
Anaerobutyricum hallii showed differential responses depending on the specific fibre or fibre combination used.
Anaerobutyricum hallii was increased with psyllium husk, wheat dextrin, and banana resistant starch.
Anaerobutyricum hallii was decreased with a mixture of sugarcane fibre and cassava resistant starch (p < 0.0001).
This demonstrates that fibre combinations can have opposing microbial effects compared to individual fibres, highlighting the importance of studying fibre interactions.
Results
Fermentation kinetics of dietary fibres were distinctly categorised into four temporal categories.
The four categories established were 'fast', 'medium', 'slow', and 'poorly-fermentable'.
Eight distinct dietary fibres were examined in the study, fermented both individually and in combination.
The authors describe this as establishing 'a standardised framework for describing fermentation rates across studies'.
Temporal dynamics of both gut microbial composition and metabolite production were evaluated to characterise these rates.
Methods
The study used an n-of-1 longitudinal single-subject design to evaluate individual-level fermentation responses to dietary fibres.
The study examined responses to eight distinct dietary fibres, fermented both individually and in combination.
The authors note that prior studies typically used pooled faecal material and isolated fibres, which they describe as 'creating unrealistic environments'.
The n-of-1 design was intended to better reflect natural circumstances and characterise fermentation at an individual level.
The study evaluated temporal dynamics of gut microbial composition and metabolite production.
What This Means
This research suggests that combining different types of dietary fibre can produce greater health-promoting effects than consuming individual fibres alone. The study used an innovative single-person longitudinal design — rather than averaging results across many people or using pooled stool samples — to examine how eight different dietary fibres affected gut bacteria and the production of beneficial compounds called short-chain fatty acids (SCFAs), particularly butyrate, which is associated with gut health. A key finding was that blending sugarcane fibre with cassava resistant starch produced significantly more butyrate than either fibre on its own, indicating a synergistic interaction between these two fibre types.
The research also found that different fibres selectively promoted different beneficial bacteria. For example, inulin and pectin encouraged the growth of Bifidobacterium species, while psyllium husk, wheat dextrin, and banana resistant starch increased a bacterium called Anaerobutyricum hallii — though interestingly, the sugarcane and cassava combination actually decreased this same bacterium. This highlights how combining fibres can have complex and sometimes unexpected effects on the gut microbiome that differ from what individual fibres would predict.
The study also proposed a standardised way to describe how quickly different dietary fibres are broken down by gut bacteria, categorising them as 'fast', 'medium', 'slow', or 'poorly-fermentable'. This research suggests that strategically selecting and combining dietary fibres could be a practical approach to personalising diets for better gut health outcomes, and that testing fibres in combinations — rather than in isolation — is important for understanding their true effects in the body.
Opperman C, Lloyd C, Ratanpaul V, Van T, Brennan C, Eri R. (2026). Engineering SCFAs with dietary fibre combinations: insights from a kinetic-microbiome single-subject longitudinal study.. Food research international (Ottawa, Ont.). https://doi.org/10.1016/j.foodres.2026.118846