Diets with increases whole-grain foods, high
in soluble or insoluble fiber, are associated
with a reduction in blood pressure in individuals
with slightly elevated cholesterol, according
to researchers in Maryland.
Dr. Kay M. Behall and colleagues from the U.S.
Department of Agriculture,
Beltsville, examined the effects on blood pressure
of whole-grain diets containing insoluble fiber
(whole wheat and brown rice) and soluble fiber
(barley).
Seven men, nine premenopausal women, and nine
postmenopausal women, all with mildly high cholesterol,
were put on the controlled Step I
American Heart Association diet for 2 weeks.
After that, refined carbohydrates in the Step
I diet were replaced with whole-grain foods. Two
types of whole-grain diets -- whole wheat/brown
rice, barley, or half wheat-rice/half barley)
were each consumed for 5 weeks.
Blood pressure was measured weekly and weight
was measured daily before breakfast. Results of
the study are published in the September issue
of the Journal of the American Dietetic Association.
Blood pressure decreased significantly during
the all whole-grain diets. Systolic blood pressure,
the top reading, declined by 2.2 mm Hg when the
subjects consumed the Step I diet and declined
by an additional 1.4 to 6.7 mm Hg while subjects
consumed the whole-grain diets, Dr. Behall's team
reports.
Diastolic blood pressure, the lower reading,
declined by 2 mm Hg on the Step I diet and was
reduced an additional 2.9 to 3.7 mm Hg when whole-grains
were added.
Among the men, the greatest reduction in arterial
pressure was observed during the half-and-half
diet, while the greatest reduction in arterial
pressure for women occurred during the diet with
barley. Postmenopausal women were the least responsive.
Subjects lost about 1 kg during the course of
the study, a significant difference. Compared
to the Step I diet, calorie levels were significantly
higher during all whole-grain diets.
"Increasing whole-grain foods, whether high in
soluble or insoluble fiber, can reduce blood pressure
and may help control weight," the researchers
conclude.
SOURCE: Journal of the American Dietetic Association,
September 2006.
