# Physical Activity Is Associated with Gut Microbiome Features and Organic Acid Patterns in Adults Consuming Plant-Rich Diets: An Exploratory Cross-Sectional Study

## TL;DR

This study finds that physical activity is linked to healthier gut bacteria and metabolism in adults eating plant-based diets.

## Contribution

The study explores how physical activity affects gut microbiome and metabolic profiles in plant-rich diet consumers with similar pesticide exposure.

## Key findings

- Lower physical activity was associated with reduced gut bacterial diversity and altered metabolic markers.
- Higher physical activity was linked to more balanced gut bacteria and metabolic profiles.
- Dietary pesticide exposure levels were similar between the physical activity groups.

## Abstract

People who eat mostly fruits, vegetables, and other plant-based foods are often considered to have a healthy diet. However, these foods can also contain small amounts of pesticide residues, especially when they are conventionally grown. At the same time, lifestyle factors such as physical activity may influence how the body responds to dietary and environmental exposures. In this study, we examined adults who followed predominantly plant-based diets and reported digestive symptoms. All participants were exposed to similar levels of pesticide residues through their daily food intake. We compared individuals with lower and higher levels of physical activity to see whether lifestyle differences were associated with changes in gut bacteria and metabolic markers. We found that people with lower physical activity more often had reduced diversity of gut bacteria and different patterns of bacteria linked to digestion and metabolism. They showed differences in selected intermediary metabolic markers, while several other metabolic pathways did not differ between groups. In contrast, individuals who were more physically active tended to show more balanced gut bacterial and metabolic profiles, despite having similar dietary exposure. These findings suggest that physical activity may play an important role in shaping gut health and metabolic responses in people consuming plant-rich diets. Understanding how lifestyle factors interact with diet may help improve strategies for maintaining digestive and metabolic well-being.

Background: Plant-rich dietary patterns are widely associated with metabolic and gastrointestinal health benefits. However, individuals consuming predominantly plant-based foods may also experience chronic low-dose exposure to dietary pesticide residues. At the same time, physical activity is recognized as an important lifestyle factor influencing metabolic health and gut microbiome composition. How microbiome features and microbiome-related metabolic profiles vary according to physical activity level in adults consuming plant-rich diets and reporting gastrointestinal symptoms remains insufficiently characterized. Objective: To explore associations between physical activity level, gut microbiome characteristics, and urinary organic acid patterns in adults consuming predominantly plant-rich diets and experiencing gastrointestinal symptoms, within a cohort characterized by comparable estimated dietary pesticide exposure used as a contextual dietary background variable. Methods: This cross-sectional observational study included 93 adults consuming ≥50% plant-based foods for at least six months and reporting persistent gastrointestinal symptoms. Participants were stratified according to physical activity level using WHO-based thresholds (<150 vs. ≥150 min/week of moderate-intensity activity). Stool microbiota were assessed using a targeted quantitative PCR panel, and microbial diversity was summarized using a laboratory-derived Shannon index. A voluntary subgroup (n = 50) underwent targeted urinary organic acid analysis (LC–MS/MS). Dietary pesticide exposure was indirectly estimated using national surveillance data combined with individual dietary records and was applied uniformly across groups. Analyses were primarily descriptive and exploratory; results are presented as associations. Results: Estimated dietary pesticide exposure did not differ between physical activity groups. Participants with lower physical activity were older and exhibited lower microbial diversity and a higher prevalence of reduced abundance in selected commensal taxa. Differences were observed in selected intermediary organic acid markers, while no statistically significant difference was found for the bile acid-related indicator. Several cross-domain correlations were identified between microbial features and metabolite patterns. However, given the cross-sectional design, age imbalance between groups, and subgroup-based metabolomic analyses, the findings should be interpreted as hypothesis-generating rather than indicative of independent effects of physical activity. Conclusions: In adults consuming plant-rich diets and reporting gastrointestinal symptoms, physical activity level was associated with distinct microbiome and microbiome-related metabolic patterns under comparable estimated dietary pesticide exposure. These findings highlight the potential contribution of lifestyle factors to interindividual variability in gut microbial and metabolic profiles, while underscoring the need for age-adjusted, longitudinal, and biomarker-based studies to clarify directionality and mechanisms.