Experts Urge Dietary Considerations in Probiotics and Prebiotics Research

A recent Nature Microbiology publication authored by an international team of scientists emphasizes the crucial role of diet in the effectiveness of probiotics and prebiotics. The paper, convened by the International Scientific Association for Probiotics and Prebiotics (ISAPP), suggests that dietary factors may be key to understanding the variable responses individuals experience with these gut-targeting interventions.

While previous studies have shown that probiotics and prebiotics can influence health in various ways, responses to these interventions can differ widely among individuals. The authors attribute much of this variation to differences in diet, a factor that has been largely overlooked in past research. As the authors point out, diet significantly influences the gut microbiome’s composition and function, particularly through undigested carbohydrates like dietary fibers, which serve as substrates for microbial metabolism in the gut.

“Although more studies evaluating the influence diet has in responses to probiotic and prebiotic intake are clearly needed, the totality of evidence from research investigating diet and the gut microbiome strongly indicates that background diet is a major determinant of probiotic and prebiotic efficacy,” explained Maria Marco, PhD, professor of food and science at University of California, Davis and co-lead author of the paper along with Kevin Whelan, PhD, from King’s College London.

In their perspective, the authors discuss research that has shown a clear connection between dietary habits and the efficacy of probiotics and prebiotics. For instance, in a study on individuals with metabolic syndrome, dietary factors were instrumental in distinguishing responders from non-responders to a probiotic intervention. Another study found that participants with higher baseline fiber intake showed a greater microbiome response to prebiotics and reported feeling fuller compared to those with lower fiber intake.

“It was rather shocking to find that diet has been overlooked as a variable for predicting and understanding responses to probiotics and prebiotics,” said Dr. Marco. “These dietary amendments are affected by diet’s impacts on the intestinal environment in the case of probiotics and are substrates for diet-modulatory microorganisms in the case of prebiotics.”

The paper explains that diet can influence the intestinal environment in multiple ways, including changes to gastric pH, the secretion of digestive enzymes, and energy availability for gut cells. These factors directly shape the conditions in which prebiotics and probiotics operate, impacting their effectiveness.

“It is no longer enough to measure the host microbiome as a factor in understanding the response to probiotics and prebiotics,” said Dr. Whelan. “To understand the bigger picture, it’s necessary to also know how diet shapes the microbiome and determines probiotic and prebiotic response.”

To help researchers better incorporate dietary factors into future studies, the authors provided ten key recommendations for the design, conduct, and reporting of probiotic and prebiotic trials. Among these recommendations are:

• Considering the harmonization of participants’ diets before beginning the intervention.
• Providing precise guidance on dosing and timing for the probiotic or prebiotic.
• Timing clinical trials to avoid holidays or other periods when participants’ diets may significantly deviate from normal.
• Selecting dietary assessment methods that best address the research question, whether short- or long-term.
• Including a dietitian or nutrition expert on the research team to facilitate accurate dietary assessment and interpretation.

By taking these recommendations into account, the authors believe researchers may be able to better understand and harness the health benefits of probiotics and prebiotics. These adjustments could enable more personalized and effective approaches to health interventions involving gut microbiome modulation.

For integrative practitioners, this paper serves as a call to action to consider dietary context in their recommendations for probiotics and prebiotics, potentially enhancing therapeutic outcomes by tailoring these interventions to individual dietary backgrounds.