Higher Dietary Non-enzymatic Antioxidant Capacity Is Associated with Decreased Risk of All-Cause and Cardiovascular Disease Mortality in Japanese Adults.

BACKGROUND: Few studies have assessed associations of non-enzymatic antioxidant capacity (NEAC) in the overall diet with all-cause or specific mortality, and their results have been inconsistent. OBJECTIVES: The present study investigated the association between dietary NEAC and all-cause or cause-specific mortality. METHODS: The study was a large-scale population-based prospective cohort study in Japan consisting of 42,520 men and 50,207 women aged 44-76 y, who had no history of cancer, stroke, ischemic heart disease, or chronic liver disease. We evaluated FFQ-based dietary NEAC with use of published databases in which the NEACs of individual foods were analyzed by ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays. Dietary NEAC was calculated by multiplying the estimated NEAC with the consumed amount and summing up those values for all foods, and was categorized in quartiles. We identified death and cause of death with use of residential registry and death certificates. HRs and 95% Cls for death from the second survey, which was conducted from April 1995 to December 2014 were estimated with Cox proportional hazards regression analysis. RESULTS: After 1,498,308 person-years of follow-up, 12,978 total deaths occurred. The multivariable-adjusted HRs (95% Cls) for all-cause mortality for the highest compared with the lowest quartile of FRAP and ORAC were 0.85 (0.80, 0.89) and 0.84 (0.79, 0.89), respectively. Dietary NEACs were inversely associated with mortality from cardiovascular disease (CVD), but not from cancer. The multivariable-adjusted HRs (95% Cls) for CVD for the highest compared with the lowest quartile of FRAP and ORAC were 0.83 (0.75, 0.92) and 0.79 (0.70, 0.89), respectively. CONCLUSIONS: Higher dietary NEACs from FRAP and ORAC were associated with lower risk of all-cause mortality and mortality from CVD in Japanese adults.

High Dietary Acid Load Score Is Associated with Increased Risk of Type 2 Diabetes in Japanese Men: The Japan Public Health Center-based Prospective Study.

BACKGROUND: Diet-induced metabolic acidosis has been linked to cardiometabolic abnormalities in Westerners, but the evidence on this issue is scarce in Asians. OBJECTIVE: The present study prospectively examined the association between dietary acid load and type 2 diabetes (T2D) in Japanese adults. METHODS: Study participants were 27,809 men and 36,851 women, aged 45-75 y, who completed a dietary questionnaire of the second survey of the Japan Public Health Center-based Prospective Study and had no previous history of T2D. Dietary intake was assessed by using a validated 147-item food-frequency questionnaire. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores were derived from the nutrient intake. A multilevel logistic regression model was used to estimate ORs and 95% CIs of self-reported, physician-diagnosed T2D over 5 y, with adjustment for potential confounding variables. RESULTS: A total of 1191 cases of newly diagnosed T2D were reported. PRAL score was positively associated with T2D in men; the multivariable-adjusted ORs (95% CIs) for the lowest through the highest quartiles of PRAL were 1.00, 1.09 (0.87, 1.36), 1.10 (0.88, 1.37), and 1.25 (1.01, 1.55) (P-trend = 0.047). Further adjustment for dietary intake strengthened the association. NEAP score was not associated with the risk of T2D (P-trend = 0.20). In stratified analyses, the positive association between PRAL and T2D was confined to younger men (age <50 y; P-trend = 0.046). There was no association between dietary acid load score and T2D in women. CONCLUSION: A high dietary acid load score is associated with an increased risk of T2D in Japanese men.

Relationship between dietary non-enzymatic antioxidant capacity and type 2 diabetes risk in the Japan Public Health Center-based Prospective Study.

OBJECTIVE: Intake of antioxidants may reduce the risk for type 2 diabetes (T2D) by reducing oxidative stress. However, it is unclear whether dietary non-enzymatic antioxidant capacity (NEAC), which represents the cumulative action of dietary antioxidants and their synergistic effects in foods, is associated with decreased T2D risk. The aim of this study was to investigate the associations between dietary NEAC and T2D. METHODS: The study included 64 660 adults (27 809 men and 36 851 women), 44 to 76 y of age without history of T2D in the Japan Public Health Center-based Prospective Study. Dietary NEAC was estimated using databases of NEAC measurements compiled from results for three different assays: ferric reducing-antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and total radical-trapping antioxidant parameter (TRAP). A multiple logistic regression model was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of self-reported physician-diagnosed T2D over 5 y with adjustment for potential confounders. RESULTS: In all, 1191 cases of newly diagnosed T2D were reported. Dietary NEACs were not significantly associated with T2D. The multivariate-adjusted ORs were 1.04 (95% CI, 0.88-1.23; Ptrend = 0.56) for FRAP, 1.11 (95% CI, 0.93-1.32; Ptrend = 0.26) for ORAC, and 0.99 (95% CI, 0.84-1.18; Ptrend = 0.84) for TRAP. Similar associations were observed in men and women (Pinteraction = 0.46 for FRAP, 0.35 for ORAC, and 0.63 for TRAP). In stratified analyses of major prooxidant factors, no notable associations with smoking and obesity status were observed. CONCLUSIONS: This finding suggests that dietary NEAC may not be appreciably associated with T2D in Japanese adults.