Soy and Fish Oil Intake and Mortality in a Japanese Community

The relation between intake of fish and soy products and subsequent all-cause and cause-specific mortality was examined in a cohort of 13,355 male and 15,724 female residents of Takayama, Gifu, Japan. A diet that included soy and fish intake was assessed in 1992 by using a validated semiquantitative food frequency questionnaire. Over 7 years of follow-up, 2,062 participants (1,163 men and 899 women) died. For men, the highest compared with the lowest quintile of total soy product intake was marginally significantly inversely associated with total mortality after adjustment for total energy and nondietary covariates (hazard ratio = 0.83, 95% confidence interval: 0.69, 1.01; p for trend = 0.07). After adjustment for nondietary covariates, a decreased hazard ratio for the highest compared with the lowest quintile of total soy product intake was also observed for women (hazard ratio = 0.83, 95% confidence interval: 0.68, 1.02; p for trend = 0.04). Additional adjustment for dietary factors significantly associated with total mortality did not attenuate these associations. For women but not for men, n-3 fatty acids from fish were significantly inversely associated with total mortality. Results showed that soy intake may have moderate but beneficial effects on total mortality.