We’ve known for some time that whole grains can support overall health, with studies suggesting that they might help with everything from lowering cholesterol levels to improving insulin sensitivity and decreasing cancer risk.
The new study published in the American Journal of Clinical Nutrition looked more closely at how whole grains might help improve heart health—by measuring blood pressure, cholesterol levels, markers of inflammation, and insulin sensitivity in 206 people between ages 40 and 65. All of the people were at somewhat high risk for heart disease; some were overweight, most were relatively inactive, and many had metabolic syndrome (a cluster of heart disease risk factors) or moderately elevated cholesterol levels.
After four weeks of eating a diet that included only refined grains, the people were split into two groups. One group was prescribed a diet rich in whole grains, including either three servings of whole wheat foods per day (70 to 80 grams of whole wheat bread and 30 to 40 grams of whole wheat cereals) or one serving of whole wheat and two servings of oats per day. The other group was instructed to continue eating refined grains.
After 12 weeks, systolic blood pressure decreased significantly among those people eating whole grains compared with those in the refined grains group. Reducing blood pressure by this amount could translate to a 15% drop in the incidence of heart disease and a 25% decrease in stroke.
Markers of inflammation and insulin sensitivity were not that different between groups, but cholesterol levels actually went down slightly in the refined grains group.
Intake of several vitamins, including vitamins B6 and D, was much lower in the whole grains group, presumably because of fortification of the refined grains. “Such fortification did not appear to have any cardiovascular benefits, however,” said the study’s lead author, Paula Tighe, MD. “This may indicate that the potential bioactivity of the micronutrients is more marked when part of the natural grain product is present compared with the fortified foods.”
Making whole grains a regular part of your diet is easier than ever, with whole grain versions of virtually every food popping up on grocers’ shelves everywhere. Whole grain pastas are easy to find (and tastier than in the past), as are whole wheat and multigrain breads. White whole wheat flour can turn even the most finicky eater into a whole grain-lover.
(Am J Clin Nutr 2010;92:733–40)