Interactions between Human Gut Microbiome Dynamics and Sub-Optimal Health Symptoms during Seafaring Expeditions

Area of Science:

• Microbiome research
• Human health in extreme environments
• Gastroenterology

Background:

• Long ocean voyages impose unique environmental pressures on crew, potentially leading to chronic diseases and sub-optimal health.
• While gut microbiome dysbiosis is linked to chronic diseases, its specific correlation with sub-optimal health in isolated populations remains unclear.

Purpose of the Study:

• To investigate the relationship between gut microbiome composition and sub-optimal health status in crew members during a long sea expedition.
• To identify symptoms, microbial signatures, and predictive biomarkers for a newly defined "seafaring syndrome" (SS).

Main Methods:

• Shotgun metagenomics of stool samples and health questionnaires were used to evaluate 77 crew members before and after a 135-day voyage.
• Statistical analysis identified core symptoms constituting SS and correlated them with gut microbiome alterations.
• A Random Forest model was developed to predict SS using pre-voyage biomarkers.

Main Results:

• Five core symptoms (abnormal defecation, insomnia, poor sleep, nausea, overeating) defined "seafaring syndrome" (SS) in 55% of crew members.
• SS showed a significant correlation with gut microbiome perturbations, distinct from individual symptoms.
• A predictive model using 28 pre-voyage biomarkers accurately predicted SS (84.4% accuracy), validated in a separate cohort.

Conclusions:

• Sub-optimal health during long voyages, termed "seafaring syndrome," is strongly associated with specific gut microbiome dynamics.
• A distinct microbial signature characterizes SS, allowing for prediction even before exposure to the voyage environment.
• Findings offer insights into potential health management strategies for extreme environments and prediction of other dysbiosis-related diseases.