Aug. 10, 2007 -- Eating just one daily serving of whole grains may help prevent high blood pressure -- and more servings could slash your risk even further.
So says a study published in The American Journal of Clinical Nutrition.
Study participants' odds of developing high blood pressure over a decade fell by 4% with each daily serving of whole grains.
What Are Whole Grains?
Whole grains, which provide all edible parts of the grain, include whole-grain corn, oats, popcorn, brown rice, whole rye, whole-grain barley, buckwheat, and quinoa (pronounced "keen-wah").
The new study tracks whole-grain intake in nearly 29,000 U.S. women who are health care workers.
When the study started in 1992, the women were at least 45 years old and were in their early to mid-50s, on average. They completed surveys about the foods they ate during the previous year.
The women were followed for 10 years, on average. During that time, a total of 8,722 women in the group were newly diagnosed with high blood pressure (hypertension).
Compared to women who reported eating less than half a daily serving of whole grains, women who claimed to eat at least four daily servings of whole grains were about 23% less likely to be diagnosed with high blood pressure during the study.
Those findings weren't affected by other factors including age, vigorous exercise, smoking, and other dietary habits.
Refined grains, such as white bread, showed no effect on the women's odds of developing high blood pressure.
The fiber and nutrients in whole grains may have helped prevent high blood pressure, write the researchers, who included Lu Wang, MD, of the preventive medicine division at Harvard Medical School and Brigham and Women's Hospital in Boston.
The study has some limits. The women only completed the survey once, so any dietary changes they made over the years aren't reflected in the data. Also, some women may have misreported their dietary habits. It's also not clear if the findings apply to other groups of people.
Ready to add more whole grains to your diet but not sure where to start?
You could swap refined grains for whole grains -- for instance, switching from white rice to brown rice. You can also find whole grains in many products including breakfast cereals and breads.
At least half of your grains should be whole grains, according to the U.S. government's dietary guidelines.
But be a savvy shopper. Buzzwords such as "multigrain," "100% wheat," and "stone-ground" aren't the same as "whole grain."
Also, know that not all brown-colored breads are made from whole grains. The bottom line: Read food labels carefully when shopping for whole grains.
Of course, whole grains don't solely determine your blood pressure. Your age, sex, race, lifestyle, and other dietary habits also matter.