Dietary Quality and Microbiome Profiles among Rectal Cancer Patients: A Cross-Sectional Pilot Study.

Several gut bacterial genera showed positive correlations with dietary quality scores (PDQS) at the end of neoadjuvant chemoradiotherapy in rectal cancer patients.

• Parvimonas, Caproiciproducens, and uncultured Eggerthellaceae abundances positively correlated with PDQS scores
• Spearman's rho ranged from 0.36 to 0.50 for these positively correlated genera
• Dietary quality was assessed using the Prime Diet Quality Score (PDQS) via 24-hour dietary recall
• The study included 30 rectal cancer patients who provided stool samples for 16S rRNA gene sequencing

Multiple gut bacterial genera showed negative correlations with dietary quality scores at the end of neoadjuvant chemoradiotherapy.

• Prevotella, Rothia, Peptostreptococcus, Paeniclostridium, Enterococcus, and Howardella correlated negatively with PDQS scores
• Spearman's rho ranged from -0.43 to -0.36 for these negatively correlated genera
• 16S rRNA gene data were analyzed using QIIME2

Predicted functional pathways related to B-vitamin biosynthesis and enzyme cofactor biosynthesis were correlated with higher dietary quality scores.

• Pathways related to B-vitamin biosynthesis and enzyme cofactor biosynthesis were associated with higher PDQS scores
• Specifically, B5/pantothenate (phosphopantothenate biosynthesis I) was among the correlated pathways
• Pathway predictions from 16S rRNA gene data were validated using shallow shotgun metagenomics sequencing (SMS) in a subset of 17 participants
• SMS data were analyzed using HUMAnN2

Mean abundances of bacterial species predicted to encode the vitamin B5-CoA biosynthesis pathway were greater in the high dietary quality group.

• Three bacterial species encoding vitamin B5-CoA biosynthesis pathways were prominent in high-dietary-quality participants
• This finding was derived from the subset of 17 participants who underwent shallow shotgun metagenomics sequencing
• The pantothenate and acetyl-coenzyme A biosynthesis pathways were specifically examined for differentially abundant bacterial species among dietary quality groups

This was a cross-sectional pilot study examining gut microbiome profiles and dietary quality in rectal cancer patients at the end of neoadjuvant chemoradiotherapy.

• Sample size was 30 rectal cancer patients providing stool samples for 16S rRNA gene sequencing
• A subset of 17 participants underwent shallow shotgun metagenomics sequencing to validate pathway predictions
• Dietary quality was calculated using the Prime Diet Quality Score (PDQS) from 24-hour dietary recall
• The study design was cross-sectional, and the authors characterized it as a pilot study