Dietary acid load and mortality in the Japan Multi-Institutional Collaborative Cohort Study

The impact of diet on the body acid-base balance may be related to the risk of various chronic diseases. This prospective cohort study examined the relationships between the dietary acid load and all-cause and cause-specific mortalities in a large Japanese population. The data of 74,293 participants (aged 35-69 years in the baseline survey) in the Japan Multi-Institutional Collaborative Cohort Study were analyzed. The dietary acid load was estimated using the net endogenous acid production (NEAP) score. Cox proportional hazards regression analyses were performed to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cause-specific mortalities according to the quartiles of the energy-adjusted NEAP score after adjustments for potential confounders. During a mean follow-up of 11.6 years, 3,755 deaths were identified. Participants with higher NEAP score had increased HR of all-cause (HR 1.18, 95% CI 1.07-1.29) and cause-specific death including cerebrovascular disease death. Sex-stratified analyses showed that NEAP scores were significantly associated with higher HR of all-cause and cause-specific death, including cerebrovascular disease death in male participants, but not in female participants. This study suggests that the dietary acid load may be associated with all-cause and cause-specific mortalities in Japanese male adults.