Abstract
- Background
Cranberries (Vaccinium macrocarpon) are widely associated with numerous health-promoting benefits, which are largely attributed to their exceptionally high content of bioactive (poly)phenols, particularly flavan-3-ols. However, clinical trials investigating these physiological effects have frequently reported heterogeneous outcomes, partly driven by high inter-individual variability in how host gut microbiota metabolize and interact with these compounds. While extensive preclinical and in vitro models have demonstrated the capacity of cranberry constituents to actively modulate microbial communities, robust clinical evidence in human subjects remains scarce. Furthermore, recent phytochemical analyses indicate that commercial cranberry extracts are also rich in specific oligosaccharides, which may synergistically contribute to their overall prebiotic bioactivity. This clinical study was designed to comprehensively characterize the (poly)phenolic and oligosaccharidic composition of a standardized commercial cranberry extract and evaluate its efficacy in positively modulating the gut microbiota of human subjects.
- Methods
A targeted clinical intervention study was conducted involving 28 healthy human participants supplemented with a standardized (poly)phenol- and oligosaccharide-rich cranberry extract over a short-term four-day intervention period. High-throughput genomic sequencing and microbial profiling were utilized to analyze baseline and post-intervention fecal samples, evaluating shifts in microbial composition, alpha and beta diversity, and specific bacterial taxa abundances. Concurrently, plasma and fecal short-chain fatty acid (SCFA) profiles were quantified. To examine inter-individual variability in metabolic and microbial responses, participants were further stratified based on distinct baseline enterotypes and microbiota alterations observed following supplementation.
- Results
Following a brief four-day supplementation protocol, the cranberry extract elicited a rapid, robust bifidogenic effect, characterized by a statistically significant proliferation of Bifidobacterium populations. This was accompanied by a marked enrichment in the relative abundance of key butyrate-producing bacterial genera, including Clostridium and Anaerobutyricum. Furthermore, systemic and fecal short-chain fatty acid profiles were significantly altered, demonstrating a decreased acetate ratio alongside a notable increase in the proportion of beneficial butyrate. Stratification analyses based on inter-individual microbial variability revealed that participants harboring a baseline enterotype characterized by the presence of Prevotella experienced a selective, favorable increase in Faecalibacterium abundance in response to the cranberry extract.
- Conclusions
Short-term supplementation with a (poly)phenol- and oligosaccharide-rich cranberry extract rapidly induces a powerful bifidogenic effect, enhances butyrate-producing bacteria, and favorably alters short-chain fatty acid ratios in humans. Moreover, baseline gut microbiota structures—such as Prevotella-dominant enterotypes—modulate individual microbial responsiveness, highlighting the importance of personalized, microbiome-targeted nutritional strategies.
https://www.nature.com/articles/s41522-024-00493-w