Gut Microbiota Diversity and Composition Across Shift Types and the Effects of Walnut Supplementation-An Observational and Interventional Study.

Overall gut microbiota composition did not differ between the beginning and end of shifts, by shift type, or following walnut supplementation.

• Study used a within-person design with 13 rotating shift workers.
• GM was analyzed via 16S rRNA sequencing.
• Comparisons were made across morning, afternoon, and night shifts.
• No significant compositional differences were found between the observational and interventional phases.

Bacterial diversity showed a significant decrease at the end of the night shift during the observational period.

• The decrease in diversity at the end of the night shift was statistically significant (p = 0.03).
• This decline was observed during the three-week observational period.
• The significant decrease in diversity at the end of the night shift was not observed during walnut supplementation.
• Diversity remained stable across all other shift types and time points.

Gut microbiota clustered strongly by individual subject rather than by shift type or dietary intervention.

• The within-person design with 13 shift workers allowed for individual-level GM tracking.
• GM clustering by subject was described as 'strong'.
• This finding suggests high inter-individual variability in GM composition.
• Subject identity was a dominant factor in GM composition regardless of shift type or supplementation.

A healthier diet correlated with greater mean gut microbiota diversity among participants.

• The correlation between diet quality and mean GM diversity was r = 0.64 (p = 0.02).
• This was a statistically significant positive correlation.
• The analysis was conducted across the 13 rotating shift worker participants.
• Diet quality was assessed alongside GM diversity measured via 16S rRNA sequencing.

The study involved a three-week observational period followed by a three-week walnut supplementation intervention in rotating shift workers.

• Participants were 13 rotating shift workers observed across morning, afternoon, and night shifts.
• After the observational period, participants added a daily serving of walnuts to their habitual diet for three additional weeks.
• GM was analyzed via 16S rRNA sequencing, assessing diversity and bacterial composition across shift types and between phases.
• The study used a within-person design, allowing each participant to serve as their own control.

Shift workers are at elevated risk of chronic diseases due to circadian rhythm disruption, suboptimal lifestyle behaviors, and potentially altered gut microbiota.

• Circadian rhythm disruption is identified as a key mechanism linking shift work to chronic disease risk.
• Suboptimal lifestyle behaviors are cited as contributing factors.
• Altered gut microbiota is proposed as a potential pathway to chronic disease in shift workers.
• This background context motivated the investigation of GM diversity and composition across shift types.