Prebiotics and cognitive decline in older adults: design of the PRECODE randomised controlled trial
This paper describes only the protocol of an incomplete RCT; no efficacy data are available to determine direction of effect.
| Outcome | Grade | Direction | Effect | Studies |
|---|---|---|---|---|
| Working memory (fMRI and neuropsychological) | D | — Insufficient | não disponível — protocolo sem resultados | — |
| Gut microbiome composition | D | — Insufficient | não disponível — protocolo sem resultados | — |
| Plasma metabolites (SCFAs, indoles) | D | — Insufficient | não disponível — protocolo sem resultados | — |
| Inflammatory biomarkers | D | — Insufficient | não disponível — protocolo sem resultados | — |
| Quality of life | D | — Insufficient | não disponível — protocolo sem resultados | — |
Context
The microbiota-gut-brain axis is a biologically plausible target for prevention of age-related cognitive decline. Prebiotic fibres (chicory inulin, resistant dextrin, seaweed beta-glucans) may modulate microbial composition and metabolites linked to cognition. Robust clinical evidence in subjective cognitive decline populations is lacking, and the PRECODE trial aims to address this gap.
What the study showed
No efficacy results are presented — this is solely a protocol paper. No primary or secondary outcome data are available. No effect estimates, confidence intervals, or p-values can be reported.
How it was done
Protocol publication for a double-blind, randomised, placebo-controlled trial (NCT06433037) targeting older adults with SCD. Methods include functional MRI, gut microbiome analysis, plasma metabolomics, and neuropsychological batteries. Final sample size and duration were not specified in the provided text.
Effect magnitude
No effect size is calculable — trial is not yet completed. Power calculation parameters were not detailed in the available text.
Limitations
Complete absence of outcome data makes efficacy appraisal impossible. The provided text is fragmented (introduction and discussion repeated without full methods or results), precluding RoB 2 risk-of-bias assessment. Clinical applicability remains undetermined until results are published.
In clinical practice
No practice change is supported by this paper. Clinicians should await PRECODE trial results before recommending this intervention for cognitive decline prevention in older adults.
What is still missing
Primary and secondary outcome data from PRECODE (NCT06433037) must be published. Subsequent work should confirm whether microbiome changes translate into measurable, clinically meaningful cognitive benefit.