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.

饮食是胃肠道微生物组组成和功能的主要决定因素，但我们对它如何影响益生元和益生菌功效的理解是有限的。在这里，我们研究了人类研究中饮食对益生元和益生菌功效影响的当前证据，包括潜在机制。我们建议将习惯性饮食作为益生元和益生菌干预研究的一个变量。该建议基于饮食直接或通过肠道微生物组影响研究结果的潜在机制。在此背景下，我们考虑了膳食评估的挑战和机遇。最后，我们为益生元和益生菌（以及其他生物干预措施）的人体临床试验的设计、实施和报告提供建议，以考虑饮食和营养的任何影响。