A Summary of the article on “The role of the gut microbiome in the association between habitual anthocyanin intake and visceral abdominal fat in population-level analysis”
Background
The study by Jennings et al. (2020) published in The American Journal of Clinical Nutrition in February 2020 investigates the intricate relationship between dietary flavonoid intake, gut microbiome composition, and abdominal fat distribution. Previous research indicated that flavonoid intake influences the gut microbiome, which, in turn, metabolises flavonoids and may contribute to their health benefits. However, the specific contribution of the gut microbiome to the health benefits linked to flavonoid intake, particularly concerning abdominal adipose tissue, was not extensively studied.
The objective of this cross-sectional study was to examine associations between habitual intakes of flavonoid subclasses and MRI-determined visceral (VAT) and subcutaneous (SAT) adipose tissue. Uniquely, it also aimed to identify associations between these measurements and gut microbiome composition, and to determine if the gut microbiome influenced the proposed associations between flavonoid intake and abdominal fat.
Methods
The research was conducted on 618 men and women (aged 25–83 years) from the PopGen cohort in Kiel, northern Germany. Adipose tissue volumes (VAT and SAT) were precisely quantified using whole-body MRI. Dietary intake over the previous year was assessed via a self-administered 112-item Food Frequency Questionnaire (FFQ), with flavonoid content assigned from USDA and Phenol-Explorer databases. Gut microbiome composition was analysed by sequencing the V1–V2 region of the 16S ribosomal RNA gene from faecal samples. Statistical analyses used ANCOVA and structural equation modelling, with adjustments for various demographic, lifestyle, and dietary covariates.
Results
Key findings revealed significant associations:
- Higher habitual intake of anthocyanins was associated with lower amounts of VAT (T3-T1: −0.49 dm³) and a lower VAT:SAT ratio (T3-T1: −0.04). This association was more pronounced in men.
- Similarly, higher intake of anthocyanin-rich foods (strawberries, other berries, red wine) was also inversely associated with lower VAT and VAT:SAT ratio.
- Participants with the highest intakes of anthocyanins and anthocyanin-rich foods exhibited greater microbial diversity (Shannon index).
- Higher intake of anthocyanin-rich foods was linked to higher abundances of Firmicutes, Clostridiales, and Ruminococcaceae, and a lower abundance of Clostridium XIVa.
- Crucially, participants with higher microbial diversity, higher abundances of Clostridiales and Ruminococcaceae, and lower abundance of Clostridium XIVa had lower amounts of VAT.
The study found that up to 18.5% of the association between intake of anthocyanin-rich foods and VAT could be explained by the gut microbiome. Microbial diversity alone independently explained 15% of this association.
Conclusions
In conclusion, these novel data suggest that higher microbial diversity and abundance of specific taxa in the Clostridiales order may contribute to the association between higher intake of anthocyanins and lower abdominal adipose tissue. The authors propose that an increase in butyrate-producing bacteria, like Lachnospiraceae and Ruminococcaceae (which increased with anthocyanin-rich food intake), could be a plausible mechanism, as butyrate is known to protect against diet-induced obesity. While acknowledging the cross-sectional nature of the study as a limitation, the findings underscore the significant, mediating role of the gut microbiome in the metabolic benefits associated with habitual anthocyanin consumption.
References
Jennings, A., Koch, M., Jensen, M. K., Bang, C., Kassubek, J., Müller, H.-P., Nöthlings, U., Franke, A., Lieb, W., & Cassidy, A. (2020). The role of the gut microbiome in the association between habitual anthocyanin intake and visceral abdominal fat in population-level analysis. The American Journal of Clinical Nutrition, 111(2), 340–350. https://doi.org/10.1093/ajcn/nqz299
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