What is the scientific evidence for whole grains and a reduced risk of heart disease?
The large bulk of scientific evidence to support a positive role for whole grains and heart health is largely from epidemiological evidence (the study of how often diseases occur in different groups of people and why). These studies of large populations over long periods of time consistently show the benefit of whole grains in reducing the risk of cardiovascular diseases (CVD).
Repeated meta-analyses (a statistical process for pooling data from many clinical trials to produce a stronger conclusion than could be provided by any individual study) show that CVD risk is reduced by up to 30% when comparing the lowest whole grain consumers with the highest whole grain consumers.
Where possible, scientists control for factors associated with healthy lifestyles such as exercise, eating fruit and vegetables etc., however without conducting studies in controlled environments it is impossible to rule out the possibility that whole grain is a marker of a healthier lifestyle. In the future well designed controlled intervention studies will help strengthen the link between whole grain and heart health. There are currently very few published data from intervention studies conducted in free-living individuals and the results have been conflicting.
Consideration of the body of evidence available has led Governments in a number of countries to encourage consumption of whole grain, with some publishing specific targets for daily intake.