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Summary of our research
[Background]
The Japanese dietary pattern is characterized by higher consumption of rice, miso soup, pickles, green-yellow vegetables, seaweed, fish, and green tea, and lower consumption of beef and pork. Although greater adherence has been linked to lower mortality, it was unclear whether this association was consistent across different residential topographical settings in Japan.
[Study Details]
We conducted a prospective cohort study of 48,479 adults aged 40-79 years in the Japan Collaborative Cohort Study. Diet was assessed in 1988-1990 using the Japanese Diet Index 8 (JDI-8). During a median follow-up of 19.2 years, 9,304 all-cause deaths and 2,685 cardiovascular disease deaths occurred. Compared with the lowest JDI-8 quartile, the highest quartile was associated with lower all-cause mortality (adjusted hazard ratio 0.929; 95% confidence interval 0.872-0.990) and cardiovascular mortality (0.862; 0.766-0.970). Interactions with residential area were not statistically significant, and associations were directionally consistent across coastal, urban inland, flat/intermediate inland, and mountainous inland settings. However, the foods underlying the score differed by area; urban inland residents less often exceeded the sex-specific median for miso soup, rice, and fish intake.
[Future Directions]
These findings suggest that the association of the Japanese dietary pattern with mortality may extend across diverse settings within Japan. Dietary guidance should still consider local food availability and dietary culture, while maintaining beneficial foods and limiting salt. As an observational study based on a single baseline dietary assessment, the study does not establish causality. Repeated dietary measurements and finer-grained environmental assessments are needed.
https://doi.org/10.1111/ggi.70810
Researcher information
SHIMIZU Akio
Department of Rehabilitation, Mie University Hospital, Assistant Professor
Specialized area：
Dysphagia rehabilitation; Clinical nutrition management
Current research field：
・Database-based investigations of the association between nutritional status and clinical outcomes
・Proposals for dysphagia-rehabilitation interventions using 3D food printing