Whole-grain consumption associated with lower total, CVD mortality
Higher whole-grain consumption was associated with lower total mortality and CVD mortality, according to analyses of two prospective cohort studies.
However, researchers found no association between whole-grain consumption and cancer mortality.
Researchers investigated 74,341 women from the Nurses’ Health Study and 43,744 men from the Health Professionals Follow-Up Study who were free of CVD and cancer at baseline.
They stratified participants into quintiles according to whole-grain consumption, which was obtained from validated food frequency questionnaires and updated every 2 or 4 years. The primary outcomes were total mortality, CVD mortality and cancer mortality.
During 2,727,006 person-years of follow-up, Hongyu Wu, PhD, and colleagues documented 26,920 deaths.
Lower total, CVD mortality
After adjustment for age, smoking, BMI, physical activity and modified Alternative Healthy Eating Index score, higher whole-grain intake was associated with lower total and CVD mortality, but not lower cancer mortality, Wu, from the department of nutrition at Harvard School of Public Health, and colleagues found.
Compared with those in the lowest quintile of whole-grain intake, the HRs for total mortality were 0.99 (95% CI, 0.95-1.02) for the second quintile, 0.98 (95% CI, 0.95-1.02) for the third quintile, 0.97 (95% CI, 0.93-1.01) for the fourth quintile and 0.91 (95% CI, 0.88-0.95) for the highest quintile (P for trend<.001), according to the researchers.
Compared with those in the lowest quintile of whole-grain intake, the HRs for CVD mortality were 0.94 (95% CI, 0.88-1.01) for the second quintile, 0.94 (95% CI, 0.87-1.01) for the third quintile, 0.87 (95% CI, 0.8-0.94) for the fourth quintile and 0.85 (95% CI, 0.78-0.92) for the highest quintile (P for trend<.001), Wu and colleagues found.
Compared with those in the lowest quintile of whole-grain intake, the HRs for cancer mortality were 1.02 (95% CI, 0.96-1.08) for the second quintile, 1.05 (95% CI, 0.99-1.12) for the third quintile, 1.04 (95% CI, 0.98-1.11) for the fourth quintile and 0.97 (95% CI, 0.91-1.04) for the highest quintile (P for trend=.43), the researchers wrote.
Wu and colleagues estimated that every 28 g/day serving of whole grain was associated with a 5% (95% CI, 2-7) lower risk for total mortality and a 9% (95% CI, 4-13) lower risk for CVD mortality.
Bran, fiber may be key
The researchers also found an association between higher bran intake and lower CVD mortality (pooled HR=0.8; 95% CI, 0.73-0.87; P for trend>.001), but no association between germ intake and CVD mortality after adjustment for bran intake.
“These associations were independent of demographic and lifestyle predictors of mortality, as well as the overall dietary quality, and largely persisted among participants with various risk profiles,” Wu and colleagues wrote. “Fiber, primarily found in the bran, may reduce the risk of certain chronic diseases, in particular CVD, metabolic syndrome, diabetes and certain cancers. These findings further support current dietary guidelines that recommend increasing whole-grain consumption to facilitate primary and secondary prevention of chronic diseases and also provide promising evidence that suggests a diet enriched with whole grains may confer benefits toward extended life expectancy.”
Disclosure: The study was supported by grants from the NIH and the NHLBI. The researchers report no relevant financial disclosures.