The new study, published in JAMA Internal Medicine, examined the association between dietary whole grain consumption and risk of mortality in a group of more than 110,000 people – finding that eating more whole grains appears to be associated with reduced mortality, especially deaths due to cardiovascular disease (CVD), but not cancer deaths.
Led by researchers at Harvard School of Public Health (HSPH), the study finds that whole grains may decrease people’s risk of death by up to 15%.
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, said the team.
“This study further endorses the current dietary guidelines that promote whole grains as one of the major healthful foods for prevention of major chronic diseases,” said Qi Sun, assistant professor in the department of nutrition at HSPH and senior author of the study.
Sun and colleagues also reported that bran intake - a component of whole grain foods - was associated with similar beneficial effects. Indeed, bran intake was linked with up to 6% lower overall death risk and up to 20% lower cardiovascular disease (CVD)-related risk, said the team.
The Harvard-based team examined the association between eating whole grains and the risk of death using data from two large studies: 74,341 women from the Nurses' Health Study (1984-2010) and 43,744 men from the Health Professionals Follow-Up Study (1986-2010). All the participants were free of cancer and CVD when the studies began and filled out questionnaires about their diet every two or four years from the mid-1980s to 2010.
During the follow up period, the authors documented 26,920 deaths.
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% decreased risk of overall mortality and up to 15% decreased risk of CVD-related mortality.
The team further estimated that every serving (28 grams/per day) of whole grains was associated with 5% lower total mortality or 9% lower CVD mortality.
In contrast, the researchers found no association between eating whole grains and lowered cancer-related mortality risk.
While the team found that bran consumption was also associated with lower risks, they did not find any decreased risk from eating germ, another essential component of whole grains.
Source: JAMA Internal Medicine
Published online ahead of print, doi: 10.1001/jamainternmed.2014.6283
“Association Between Dietary Whole Grain Intake and Risk of MortalityTwo Large Prospective Studies in US Men and Women”
Authors: Hongyu Wu, et al