Dietary total antioxidant capacity and mortality from all causes, cardiovascular disease and cancer: a systematic review and dose-response meta-analysis of prospective cohort studies

Purpose No conclusive information is available about the association between dietary total antioxidant capacity (DTAC) and risk of mortality. Current meta-analysis of prospective cohort studies was done to summarize available findings on the association between DTAC and risk of death from all-cause, cancer and cardiovascular diseases (CVDs). Methods Online databases were searched to detect relevant publications up to January 2018, using relevant keywords. To pool data, either fixed-effects or random-effects model was used. Furthermore, linear and non-linear dose-response analyses were also done. Results In total, five prospective studies were included in the current systematic review and meta-analysis. In a follow-up period of 4.3-16.5 years, there were 38,449 deaths from all-cause, 4470 from cancer and 2841 from CVDs among 226,297 individuals. A significant inverse association was found between DTAC and all-cause mortality (combined effect size: 0.62, 95% CI 0.60-0.64). Such finding was also seen for cancer (combined effect size: 0.81, 95% CI 0.75-0.88) and CVD (combined effect size: 0.71, 95% CI 0.63-0.82) mortality. Findings from linear dose-response meta-analysis revealed that a 5 mmol/day increment in DTAC based on ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) was associated with 7% and 15% lower risk of all-cause mortality, respectively. Based on findings from non-linear dose-response meta-analysis, a significant reduction in risk of all-cause mortality was seen when increasing FRAP from 2 to 12 mmol/day (P-nonlinearity = 0.002) and ORAC from 5 to 11 mmol/day (P-nonlinearity < 0.001). Conclusions Adherence to diet with high total antioxidant capacity was associated with decreased risk of death from all-cause, cancer and CVDs.