From gut health to immune support, probiotics have become one of the most active areas of nutrition research. However, generating evidence is not always straightforward. Researchers may want to understand how a probiotic works, assess whether a larger trial is feasible, evaluate efficacy in a specific population, or study how an intervention performs in everyday life. Each of these questions requires a different type of study.
This is precisely the challenge that inspired PRODARE (PRObiotic human study Design And REporting), a new framework introduced in Advances in Nutrition. Developed by an international expert group coordinated by ILSI Europe, including researchers from Danone Research & Innovation, PRODARE aims to help researchers select, design and report human probiotic studies more effectively.
Rather than prescribing a single "best" approach, the framework recognises that different scientific questions require different forms of evidence. At the heart of PRODARE is a practical decision tree designed to help researchers navigate these choices and build stronger evidence from the start.
Key takeaways
Why study design matters
Human probiotic studies serve many different purposes. Some investigate early biological signals or safety efficacy, while others test feasibility before a larger study is launched or how an intervention performs in real-world settings.
According to David Pérez Pascual, Senior Team Leader Probiotics & Ferments at Danone Research & Innovation and co-author of the publication, selecting the right study design is essential because "different research questions require different types of evidence."
A study designed to explore mechanisms may look very different from one intended to demonstrate efficacy in a target population. When study objectives and study designs are not aligned, findings may become difficult to interpret or less useful for answering the original research question.
The quality of evidence generated in probiotic research depends on asking the right question and selecting the study design that is fit for that purpose.
- David Pérez Pascual
Senior Team Leader Probiotics & Ferments
A decision tree for stronger evidence
One of the most practical features of PRODARE is its decision tree, which guides researchers through study planning.
Building evidence is rarely a one-step process. Researchers often begin by exploring early signals, then move towards studies that assess feasibility, efficacy and real-world relevance. PRODARE helps bring structure to this journey by clarifying which type of study is best suited to each stage.
As David explains, "the PRODARE decision tree serves as a practical guide" that helps researchers navigate study planning and "encourages a more systematic and transparent decision-making process" across both academic and industry research.
The goal is not to prioritise one study type over another, but to help researchers identify which approach is most suitable for answering the question they are trying to solve.
Probiotics are not like other interventions
Choosing an appropriate study design is only part of the picture. Unlike many other health interventions, probiotics are living microorganisms. Characteristics such as strain identity, viability, formulation and dose can directly influence study outcomes.
Two studies may appear to evaluate similar probiotic interventions while differing in important product characteristics. Without clearly documenting these factors, comparing findings across studies becomes challenging.
PRODARE therefore complements existing clinical research guidance with recommendations tailored specifically to probiotics, helping researchers account for factors that influence both reproducibility and interpretation.
Looking ahead
As probiotic science continues to evolve, researchers are exploring an increasing number of health applications and research questions. The opportunity is significant, but so is the need for evidence that can be reliably interpreted, compared and built upon over time.
PRODARE was developed with this future in mind. By combining practical study-design guidance with probiotic-specific recommendations, the framework aims to support a more consistent approach to evidence generation across the field.
In a field advancing as rapidly as probiotic science, asking better questions may be just as important as finding the answers.
PRODARE raises the standard of probiotic research globally, enabling higher-quality evidence that supports both scientific discovery and innovation for human health.
- David Pérez Pascual
Senior Team Leader Probiotics & Ferments
References
Read the full publication here: Probiotic Human Study Design and Reporting (PRODARE): Recommendations to Improve Research Practice
