Whole grains are a global staple; recent research demonstrates why.
According to the Whole Grains Council, a whole grain food contains "all the essential parts and naturally occurring nutrients of the entire grain seed."
Examples of whole grains include barley, corn, quinoa, rice, rye, and wheat.
Much of the nutritional value of grains are lost during the refining process.
Findings from previous research infer that foods containing whole grains have a myriad of health benefits. These benefits include a reduced risk of certain cancers, diabetes, heart disease, and obesity, and they are thought to help maintain gut health.
Latest whole grain research
The research team, led by senior author Qi Sun, took an in-depth, large-scale look at dietary whole grains and their impact on longevity and disease.
The team analyzed data from 12 already-published papers, alongside data from unpublished sources - the National Health and Nutrition Examination Survey (NHANES) III and NHANES 1999-2004. The studies included participants from the United Kingdom, United States, and Scandinavian countries.
In all, the new analysis used data from 786,076 individuals between 1970 and 2010. The meta-analysis showed that, for each 16 gram serving of whole grains, there was a 7 percent decrease in total deaths, a 9 percent decrease in cardiovascular disease-related deaths, and a 5 percent reduction in deaths related to cancer.
The results, published this week in Circulation, showed that the effect was more pronounced as whole grain consumption increased.
Those individuals who ate 48 grams of whole grain per day had a 20 percent reduced risk of mortality, a 25 percent reduced risk of cardiovascular mortality, and a 14 percent lower risk of cancer mortality.
Although the results show an impressive effect size, the authors admit some limitations. For instance, the earlier studies used in the analysis were conducted before a consistent definition of whole grain was designed; therefore, the lists of whole grain foods varied substantially between experiments.
Additionally, the majority of participants were from Scandinavian countries and the U.S., so there is a possibility that the results are not relevant (or less relevant) for other populations.
"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."
Qi Sun, M.D., Sc.D., senior author
How does whole grain stave off death and disease?
Despite the shortfalls mentioned above, the results are backed up by many previous trials. So, how do whole grains impart their impressive life-extending ability?
There are a number of theories, but the likelihood is that a variety of mechanisms work together to produce the positive health outcomes. For instance, whole grains contain a variety of bioactive compounds, all of which could play their part.
Additionally, the higher fiber content of whole grains may lower the production of cholesterol and glucose. Whole grain's ability to induce a feeling of fullness might be one of the ways in which it helps stave off obesity and the conditions related to obesity.
However the effects are produced, Dr. Sun believes it is time for healthcare professionals to sing the praises of whole grain foods:
"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."
Because this study used a huge amount of data and supports earlier research, the results are likely to spawn questions about how diets should be modified. Alice H. Lichtenstein, D.Sc., a spokesperson for the American Heart Association, suggests that refined grains should be replaced with whole grain products rather than added to the diet.