Dietary Acid Load and Mortality from All Causes, Cardiovascular Disease, and Cancer: results from the Golestan Cohort Study.

Given the limited studies, and controversial results on association between dietary acid load and mortality from cardiovascular disease (CVD) and cancers, we aimed to investigate this association in a large population cohort study in Middle-East, with a wide range of dietary acid load.The study was conducted on the platform of the Golestan Cohort Study (GCS), which enrolled 50,045 participants in 2004-2008. Dietary intake was assessed using a validated food frequency questionnaire (FFQ). Dietary potential renal acid load (PRAL) score was calculated from nutrient intake. Death and its causes were identified, and confirmed by two or three physicians. Cox proportional hazards regression was used to estimate HRs and 95% CIs for total and cause specific mortalities. Then, the associations were modeled using restricted cubic splines.PRAL range was -57.36 to +53.81 mEq/d for men and -76.70 to +49.08 for women. During 555,142 person-years of follow-up, we documented 6830 deaths, including 3070 cardiovascular deaths, 1502 cancer deaths and 2258 deaths from other causes. For overall deaths, in final model after adjustment for confounders, participants in the first and 5th quintiles of PRAL had a higher risk of mortality compared to the second quintile of PRAL (HR: 1.08; 95% CI:1.01-1.16 and HR: 1.07; 95% CI: 1.01-1.15, respectively); P for trend <0.05). Participants in the first and 5th quintiles of PRAL had a 12% higher risk of CVD mortality compared to the Q2 of PRAL (HR: 1.12; 95% CI: 1.01-1.25 and HR: 1.12; 95% CI: 1.01-1.26, respectively; P for trend <0.05). We found that all-cause and CVD mortality rates were higher in the lowest and highest PRAL values, in an approximately U-shaped relation (P-values for the overall association and the non-linear association of energy-adjusted PRAL with total mortality were <0.001 and <0.001, and with CVD mortality were 0.008 and 0.003, respectively).Our results highlight unfavorable associations of high acidity and alkalinity of diet with the increased total and CVD mortality risk. It may be important to consider a balanced acid-base diet as a protective strategy to prevent premature death, especially from CVD.