BOSTON — Eating whole grains may decrease the risk of overall mortality by up to 9%, according to a study from the Harvard School of Public Health that involved more than 118,000 people. Risk of death from cardiovascular disease dropped even further, by up to 15%. Results of the study appeared on-line Jan. 5 in JAMA Internal Medicine.

While previous studies associate whole grain intake with a lower risk of diseases such as type 2 diabetes and cardiovascular disease, the Harvard researchers found for each serving of whole grains, the overall death risk dropped by 5% and by 9% for deaths related to cardiovascular disease.

“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 the Harvard School of Public Health and senior author of the study.

The study also involved researchers from the Albert Einstein College of Medicine in New York, the National University of Singapore and Brigham and Women’s Hospital in Boston. They examined data from 74,341 women in the Nurses’ Health Study and 43,744 men from the Health Professionals Follow-Up Study who filled out questionnaires about their diet every two to four years from the mid-1980s to 2010. All people were free of cardiovascular disease and cancer at baseline.

Researchers compared whole grain intake with mortality data over about a 25-year period. Adjustments were made for such factors as age, smoking, body mass index, physical activity and overall diet excluding whole grains. Higher whole grain intake was not associated with cancer mortality.

In another finding, bran intake was linked with up to 6% overall lower death risk and up to 20% lower risk of death related to cardiovascular disease. Switching one serving of refined grains per day with one serving of whole grains was linked with an 8% lower mortality risk related to cardiovascular disease. Switching one serving of red meat per day with one serving of whole grains was linked with a 20% lowered mortality risk related to cardiovascular disease.