Two studies, each lasting 17 weeks, were begun in February
2001 and February 2002. The first study involved men, and the second
study involved women. Participants followed a healthy diet lower in
fat and higher in fiber than that typically consumed by people in the
United States. Participants were fed diets rich in barley or grains
lower in soluble fiber, such as whole wheat and brown rice.
Although participants were chosen from diverse backgrounds,
special interest was given in choosing people identified as having high
cholesterol levels. Volunteers had to be dedicated, because all their
meals were provided by the laboratory. Samples were collected periodically
and measurements made for markers of glycemic control, energy regulation,
lipid metabolism, blood pressure, body composition, measures of satiety
(feeling of fullness), nutrient digestibility, metabolizable energy,
and energy expenditure.
Behall and Hallfrisch are continuing to analyze data.
Some early results show that glucose and insulin levels were lowered
by diets high in barley. Eating barley-containing foods improved several
cardiovascular risk factors. For example, in their study with men, they
found that increasing whole grain foods in a healthy diet could reduce
The diet with higher soluble fiber also had the greatest
effect on reducing total and low-density lipoprotein (LDL) cholesterol
levels, the so-called bad cholesterol.
"On average, total cholesterol was lowered 14 percent
in men with previously high cholesterol levels after consuming the fiber-rich
diets with low soluble fiber, 15 percent in those following diets with
mid soluble fiber, and 21 percent in those following diets with high
soluble fiber," Behall says.
Early data from the latest studies shows that these results
were more pronounced in postmenopausal women than in premenopausal women.
Studies at the laboratory in this area will continue.
"In future studies, we want to determine whether
eating moderate amounts of grains over a prolonged period can improve
intestinal health and/or increase immunity to disease," Behall
says. "We want to learn whether soluble fiber promotes weight-loss
maintenance by reducing insulin resistance. And we want to see if this
type of diet affects one's satiety after a meal."
Behall also wants to identify phytochemicals or prebiotics
found in barley and other grains. These nondigestible fibers have immuno-strengthening
properties because they encourage the growth of healthy bacteria in
the gut. Researchers will determine their bioavailability and effectiveness.
Behall hopes to ultimately identify foods, health practices, and attitudes
associated with successful weight loss maintenance.By Jim
Core, Agricultural Research Service Information Staff.
This research is part of Human Nutrition, an ARS National
Program (#107) described on the World Wide Web at www.nps.ars.usda.gov.
is with the USDA-ARS Diet
and Human Performance Laboratory, Beltsville Human Nutrition Research
Center, Bldg. 308, Beltsville, MD 20705; phone (301) 504-8682, fax (301)
1 cup granulated sugar
2 tablespoons cocoa, unsweetened
1/4 cup light margarine
1/2 cup fat-free milk
1 teaspoon vanilla extract
1/2 cup peanut butter (regular or low sodium)
2 cups flakes (works with oatmeal, wheat, or barley flakes)
Mix sugar, cocoa, margarine, milk, vanilla, and peanut butter together
in a saucepan and bring to a boil. Cook for 1 minute after mixture starts
to boil. Fold in flakes and stir until all the flakes are coated. Pour
and press mixture into a greased pan (9x9 or 9x13 inch) and refrigerate
until solid. Cut into desired size while cold. Use shaped cookie cutters
if desired (photo). Thickness will vary with the size of the pan.
"Grains Lay Claim to Health Gains" was published in
the May 2003
issue of Agricultural Research magazine.