Physicians' Academy for Cardiovascular Education

Higher whole grain consumption associated with lower mortality risk

Zong G et al., Circulation 2016

Whole Grain Intake and Mortality From All Causes, Cardiovascular Disease, and Cancer
A Meta-Analysis of Prospective Cohort Studies

 
Zong G, Gao A, Hu FB, et al.
Circulation. 2016;133:2370-2380
 

Background

Dietary guidelines endorse the consumption of whole grains (WGs) because they contain fiber, vitamins, minerals, phytochemicals, and other healthy nutrients. However, the actual intake of WG is far below the recommended quantities (48 g/d WG ingredients) [1-4].
 
Data from prospective cohort studies show that the consumption of WG is associated with decreased risk of diabetes, cardiovascular diseases (CVD) and cancer, however, there are no robust findings regarding mortality risk [5-8].
 
In this meta-analysis, the association between WG intake and risks of total, CVD, and cancer mortality was evaluated in 786,076 participants of 14 studies (most US, 3 Scandinavian and 1 UK). Median follow-up ranged from 6-28 years (1971-2010).
 

Main results

  • Pooled relative risk (RR) was for total mortality: 0.84 (95% CI: 0.80–0.88; P<0.001; I2=74%, P heterogeneity <0.001), for CVD mortality: 0.82 (95% CI: 0.79–0.85; P<0.001; I2=0.0%, P heterogeneity = 0.53), and for cancer mortality: 0.88 (95% CI: 0.83–0.94; P<0.001; I2=54%, P heterogeneity = 0.02).
  • Dose-response analysis (no WG consumption as a reference) showed total mortality RRsat 10 g/d: 0.93 (95% CI: 0.89–0.97), at 30 g/d: 0.84 (95% CI: 0.77–0.91), at 50 g/d: 0.80 (95% CI: 0.75–0.85) and at 70 g/d: 0.78 (95% CI: 0.74–0.82). All P<0.001, P trend <0.001 and P nonlinearity =0.06.
  • Dose-response analysis (no WG consumption as a reference) showed CVD mortality RRs at 10 g/d: 0.92 (95% CI: 0.88–0.96), at 30 g/d: 0.81 (95% CI: 0.75–0.89), at 50 g/d: 0.78 (95% CI: 0.72–0.84), at 70 g/d: 0.77 (95% CI: 0.68–0.87). All P<0.001, P trend <0.001 and P nonlinearity =0.10).
  • Dose-response analysis (no WG consumption as a reference) showed cancer mortality RR’s at 10 g/d: 0.96 (95% CI: 0.91–1.01; P=0.12), at 30 g/d: 0.89 (95% CI: 0.89–0.99; P=0.04), at 50 g/d: 0.85 (95% CI: 0.76–0.94; P=0.001), at 70 g/d: 0.80 (95% CI: 0.72–0.89; P<0.001). P trend <0.001, P nonlinearity =0.67.
  • RR for each 16-g/d increase in WG ingredient consumption (≈1 serving per day) was for total mortality 0.93 (95% CI: 0.92–0.94), for CVD mortality 0.91 (95% CI: 0.90–0.93) and for cancer mortality 0.95 (95% CI: 0.94–0.96).

Conclusion

In a meta-analysis of 14 cohort studies, the consumption of whole grain products was inversely and significantly associated with mortality in a dose-response manner, especially with CVD mortality. These results support current dietary guidelines that recommend increasing WG intake to replace refined grains.
 
Find this article online at Circulation
 

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