Eating at least three servings of whole grains every day could lower your risk of death, according to new research in the American Heart Association's journal Circulation.
Although dietary guidelines around the world have included whole grains as an essential component of healthy eating patterns, people aren't eating enough, according to the analysis. In the United States, average consumption remains below one serving a day, despite the long-time recommendation of three servings a day.
In the first meta-analysis review of studies reporting associations between whole grain consumption and death, researchers noted that for about every serving (16 grams) of whole grains there was a:
The more whole grains consumed, the lower the death rate. According to researchers, when three servings (48 grams) were consumed daily the rates declined:
"Previous studies have suggested an association with consumption of whole grains and reduced risk of developing a multitude of chronic diseases that are among the top causes of deaths, although data linking whole grain intake and mortality were less consistent," said Qi Sun, MD, ScD, senior author of the study and assistant professor at the Harvard T.H. Chan School of Public Health in Boston, Massachusetts. "These findings lend further support to the U.S. government's current Dietary Guidelines for Americans, which suggest higher consumption of whole grains to facilitate disease prevention."
Whole grains, such as whole wheat, oats and brown rice, contain dietary fiber, which may help improve blood cholesterol levels, and lower the risk of heart disease, stroke, obesity and Type 2 diabetes. Dietary fiber can also make you feel full longer, so you may eat fewer calories.
This analysis included 12 studies published through February 2016 and unpublished results from the National Health and Nutrition Examination Survey (NHANES) III, conducted from 1988 to 1994, and NHANES 1999-2004. Of the reviewed studies, 10 were conducted in U.S. populations, three in Scandinavian countries and one in the United Kingdom.
The combined studies involved 786,076 men and women with 97,867 total deaths, 23,597 deaths from cardiovascular disease, and 37,492 deaths from cancer.
A potential drawback of the analysis may be the use of questionnaires to assess respondents' intake of whole grains. However, Sun said questionnaires were validated against respondents' diet records to ensure reliability.
Sun noted that low-carbohydrate diets that ignore the health benefits of whole grains foods "should be adopted with caution," as they may be linked to higher cardiovascular risk and mortality.
"Based on the solid evidence from this meta-analysis and numerous previous studies that collectively document beneficial effects of whole grains, I think healthcare providers should unanimously recommend whole grain consumption to the general population as well as to patients with certain diseases to help achieve better health and perhaps reduce death," Sun said.
The American Heart Association recommends a heart-healthy dietary pattern emphasizing fruits, vegetables, whole grains and other nutritious foods and specifically that at least half of grain consumption should be whole grains. Whole grains provide many nutrients, such as fiber, B vitamins, and minerals, which are removed during the refining process.
American Heart Association spokesperson Alice H. Lichtenstein, DSc, noted that refined grains should be replaced with whole grain products rather than added to the diet.