Resistant starch vs polydextrose: distinct bile acid and microbiome effects
النشاء المقاوم مقابل البولي ديكستروز: تأثيرات مختلفة على أحماض الصفراء والميكروبيوم
Journal: European journal of nutrition
University: Not specified in abstract
Study Type: RCT
Evidence Level: moderate
Participants: 74
Published:
30-Second Summary
In a double-blind, randomized, placebo-controlled 2×2 factorial trial, healthy adults consumed 23 g/day resistant starch and/or 12 g/day polydextrose for 50 days; plasma (n=74) and faecal (n=50) bile acid profiles were measured by UPLC‑MS. The two fibres produced distinct changes in plasma and faecal bile acid profiles that were associated with shifts in gut microbiota composition.
1-Minute Summary
This double-blind, randomized, placebo-controlled 2×2 factorial RCT tested 23 g/day Hi‑maize®260 (type 2 resistant starch) and/or 12 g/day Litesse®Ultra™ (polydextrose) for 50 days in healthy participants. Bile acid profiles in plasma (n=74) and faeces (n=50) were quantified by UPLC‑MS and analysed using general linear models. The study found that resistant starch and polydextrose produced distinct alterations in plasma and faecal bile acid profiles, and these alterations were associated with changes in gut microbiota composition. Results come from a single trial in healthy adults and highlight microbiota‑linked effects on bile acid metabolism that warrant replication and further mechanistic work.
3-Minute Summary
This double‑blind, randomised, placebo‑controlled 2×2 factorial trial evaluated how two fermentable fibres — resistant starch (RS; 23 g/day Hi‑maize®260, type 2) and polydextrose (PD; 12 g/day Litesse®Ultra™) — affected bile acid (BA) profiles in healthy adults after 50 days. BA profiling by ultra‑performance liquid chromatography–mass spectrometry was performed on plasma (n=74) and faecal (n=50) samples and analysed using general linear models. The study found that RS and PD produced distinct alterations in both plasma and faecal BA composition after supplementation. Importantly, observed BA changes correlated with shifts in gut microbiota composition, consistent with microbiota‑mediated effects on BA metabolism. The trial’s factorial design allowed independent and combined effects of RS and PD to be assessed. Overall, results suggest that different fermentable fibres can differentially modulate systemic and luminal bile acid pools over a moderate intervention period, and that these effects are linked to changes in fibre‑fermenting and bile‑metabolising microbial taxa. Findings support the concept that dietary fibre types may influence host bile acid physiology via the gut microbiota, but they stop short of clinical or therapeutic claims and require further mechanistic and longer‑term studies to determine health relevance.
Full Analysis
Design and methods: This well‑controlled 2×2 factorial RCT enrolled healthy adults and randomized them to RS (23 g/day), PD (12 g/day), both, or placebo for 50 days, with double blinding and placebo control. Bile acids in plasma (n=74) and faeces (n=50) were quantified by UPLC‑MS, and intervention effects were tested with general linear models. Microbiota composition was assessed in parallel and used to examine associations with BA changes. Key findings and interpretation: Both RS and PD altered BA profiles, but in distinct ways in plasma and faeces, indicating that fermentable fibres with different physicochemical and fermentative properties can differentially influence host bile acid pools. The association between BA shifts and changes in microbiota composition supports a microbiota‑mediated pathway — for example, fibre‑driven changes in taxa and microbial enzymatic activities (deconjugation, 7α‑dehydroxylation) can alter the balance of primary/secondary and conjugated/unconjugated BAs. Strengths: randomized, double‑blind, factorial design; objective UPLC‑MS BA quantification; integration with microbiota data. Limitations and caution: faecal BA analyses were on a smaller subset (n=50), limiting power for stool endpoints; 50 days is a moderate duration that may not capture longer‑term adaptations; the cohort of healthy adults limits generalisability to clinical populations. Implications and next steps: Findings suggest fibre type matters for BA–microbiota interactions. Mechanistic work (metagenomics, microbial enzyme assays), dose–response studies, and longer interventions are needed to confirm causal microbial pathways and to determine whether these biochemical changes translate into clinically meaningful outcomes. Language: results suggest and may support microbiota‑mediated modulation, without making therapeutic claims.Health Implications
For daily habits, these findings suggest that the type of fermentable fibre you consume may influence bile acid metabolism via the gut microbiota. Including a variety of fibre sources — such as foods naturally high in resistant starch (cooled cooked rice/potatoes, legumes, green bananas) and a range of soluble fibres — may help support a diverse microbiota and related metabolic pathways. Aim for gradual increases to avoid gastrointestinal discomfort, prioritise whole foods, and combine fibres with overall healthy eating patterns. People with specific medical conditions should consult a health professional before using high‑dose fibre supplements. These suggestions are based on biochemical and microbiome associations and do not imply therapeutic benefit.
Key Findings
- Resistant starch and polydextrose produced distinct alterations in plasma and faecal bile acid profiles after 50 days of supplementation in healthy adults.
- Observed bile acid changes were associated with shifts in gut microbiota composition, consistent with microbiota‑mediated mechanisms linking dietary fibre and bile acid metabolism.