Nutrition experts already know the benefits of whole grains to help ward off type-2 diabetes. Recent research from the UK suggests that three daily servings of whole grains could lower risk factors for cardiovascular disease (CVD) as well. According to the researchers, the large of reduction in systolic blood pressure for study participants eating whole grains was dramatic. If the study was magnified population-wide, this whole-grain diet switch could hypothetically lower the incidence of coronary artery disease by more than 15% and stroke by 25 percent.
In this randomized, controlled trial, 206 middle-aged, healthy (free of CVD, diabetes, and hypertension) men and women were followed for 16 weeks. All participants consumed a generally refined grains diet – low in whole grains – for the first four weeks, and were then assigned to a control group (refined grains), or one of two whole-grain intervention groups: wheat, or wheat and oats. The researchers provided the three daily whole grain servings (each serving was about 1oz each of bread or cereal) for the intervention groups, though participants were able to choose all other foods for the remaining 12 weeks.
They found a significant decrease in CVD risk factors among both whole grain intervention groups, as evidenced by an average 5-6 mmHg drop in systolic blood pressure versus the control group. In fact, blood pressures were noted to be dropping even by week 6 for the wheat and oats group. The study did not find reduced levels of triglycerides, cholesterol, or markers for insulin sensitivity, inflammation, or arterial stiffness with 3 daily servings of whole grains.
While the fiber content of the whole grain intervention was generally assumed to be responsible for the observed blood pressure lowering effect, the researchers are still not certain how exactly whole grains work to lower blood pressure. Furthermore, the researchers pointed out, their results differed from other studies of whole grains and CVD risk factors, which did not find a similar blood-pressure lowering effect–though such differences may be accounted for by the respective studies’ designs. These caveats aside, this study contributes to the growing body of evidence in support of of long-standing recommendations to eat more whole grains every day.