Whole-grain consumption and the risk of all-cause, CVD and cancer mortality: a meta-analysis of prospective cohort studies

Results of the relationships between dietary whole-grain consumption and the risk of all-cause, CVD and cancer-specific mortality are mixed. We summarised the evidence based on a meta-analysis of prospective cohort studies. Pertinent studies were identified by searching articles in the MEDLINE and EMBASE databases up to 20 January 2016 and by reviewing the reference lists of the retrieved articles. Random-effects models were used to calculate summary relative risks (SRR) and 95% CI. In all, eleven prospective studies (ten publications) were included in the meta-analysis. There were a total of 816599 subjects and 89251 cases of all-cause mortality. On the basis of the highest v. the lowest categories of intake, whole grains may be associated with a lower risk of mortality from all causes (SRR 0·87; 95% CI 0·84, 0·90), CVD (SRR 0·81; 95% CI 0·75, 0·89) and all cancers (SRR 0·89; 95% CI 0·82, 0·96). For each 3 servings/d increase in whole-grain intake, there was a 19% reduction in the risk of all-cause mortality (SRR 0·81; 95% CI 0·76, 0·85), a 26% reduction in CVD mortality (SRR 0·74; 95% CI 0·66, 0·83) and a 9% reduction in cancer mortality (SRR 0·91; 95% CI 0·84, 0·98). The current meta-analysis provides some evidence that high intake of whole grains was inversely associated with the risk of all-cause, CVD and cancer-specific mortality. Further well-designed studies, including clinical trials and in different populations, are required to confirm our findings.