Eating more whole grains is associated with up to 15% lower mortality—particularly cardiovascular disease (CVD)-related mortality, according to a large new long-term study from Harvard T.H. Chan School of Public Health.
The study also found that bran, a component of whole grain foods, was associated with similar beneficial effects. Bran intake was linked with up to 6% lower overall mortality and up to 20% lower CVD-related mortality.
“This study further endorses the current dietary guidelines that promote whole grains as one of the major healthful foods for prevention of majorchronic diseases,” said Qi Sun, assistant professor in the Department of Nutrition and senior author of the study.
Although eating more whole grains has been previously associated with a lower risk of major chronic diseases, such as type 2 diabetes and CVD, until now there had been limited evidence regarding whole grains’ link with mortality. HSPH researchers and colleagues looked at data from more than 74,000 women from the Nurses’ Health Study and more than 43,000 men from the Health Professionals Follow-Up Study who filled out questionnaires about their diet every two or four years from the mid-1980s to 2010. Adjusting for a variety of factors, such as age, smoking, body mass index, physical activity, and overall diet excluding whole grains, the researchers compared the participants’ whole grain intake with mortality data over an approximately 25-year period.
They found that whole grain intake was associated with up to 9% lower overall mortality and up to 15% lower CVD-related mortality. For each serving of whole grains (28g/day), overall mortality dropped by 5%, and by 9% for CVD-related mortality.
In contrast, the researchers found no association between eating whole grains and lowered cancer-related mortality. They also didn’t find any decreased mortality from eating germ, another essential component of whole grains.
Replacing refined grains and red meats with whole grains is also likely to lower mortality, according to the study. Swapping just one serving of refined grains or red meat per day with one serving of whole grains was linked with lower CVD-related mortality: 8% lower mortality for swapping out refined grains and 20% lower mortality for swapping out red meat.