Best practices for designing better clinical trials of probiotics and prebiotics (Oct 2024) Design and reporting of prebiotic and probiotic clinical trials in the context of diet and the gut microbiome Probiotics

[Michael Harrop]

• https://www.gutmicrobiotaforhealth.com/best-practices-for-designing-better-clinical-trials-of-probiotics-and-prebiotics/
• https://www.nature.com/articles/s41564-024-01831-6

Diet can impact the efficacy of prebiotics and probiotics. A new perspective article in Nature Microbiology makes 10 recommendations for designing, conducting, and reporting clinical trials of prebiotics and probiotics that support best practices in microbiome research.

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a workshop convened by the International Scientific Association for Probiotics and Prebiotics, which resulted in ten recommendations to guide the design and conduct of trials of prebiotics and probiotics:

1. Consider whether and how to harmonize the diet of the study population before intervention by using different degrees of researcher intervention
2. Participants should not be involved in religious festivals or holidays if their dietary intake is altered
3. The composition of prebiotic or probiotic, and of the delivery matrix, the source, the dose/viable cell numbers per dose of the active ingredient, and the manufacturer should be reported, considering that these variables can affect prebiotic and probiotic effectiveness
4. Details of prebiotic or probiotic intake (number of doses, timing, meals) should be reported, as well as participants’ adherence to the treatment
5. Appropriate microbiome analyses should be performed to accurately interpret the role of background diet versus intervention-specific changes
6. Dietary assessment should be performed at baseline and end of intervention in human intervention studies where diet is one inclusion or exclusion criterion
7. Dietary assessment should record microbiome-relevant diet exposures, including fermented foods and postbiotics, although current food databases do not include relevant food information that can affect the microbiome (food additives, cooking methods, and polyphenols, among others)
8. Dietary assessment should include detailed information on nutrients, food, food groups, or dietary patterns, as long as they can affect probiotics and prebiotics effectiveness
9. The method (food records, 24h recall, or food frequency questionnaire) and duration of diet assessment should depend on the research question and exposure of interest
10. A dietitian or nutritionist with research expertise should be on the team, and will be involved not only in the study design but also in accompanying the participants, and dietary assessment tools and data analyses

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Abstract​

Diet is a major determinant of the gastrointestinal microbiome composition and function, yet our understanding of how it impacts the efficacy of prebiotics and probiotics is limited.

Here we examine current evidence of dietary influence on prebiotic and probiotic efficacy in human studies, including potential mechanisms. We propose that habitual diet be included as a variable in prebiotic and probiotic intervention studies.

This recommendation is based on the potential mechanisms via which diet can affect study outcomes, either directly or through the gut microbiome. We consider the challenges and opportunities of dietary assessment in this context.

Lastly, we provide recommendations for the design, conduct and reporting of human clinical trials of prebiotics and probiotics (and other biotic interventions) to account for any effect of diet and nutrition.

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