|
Study Demonstrates How Brown Rice
Is Valuable For Cardiovascular Protection
Rice is generally thought to be a beneficial healthy addition
to the diet because it is a reliable source of fiber and Thiamine
(Vitamin B-1)
It is important to note, not all rice is equally nutritious; Brown rice might
have an advantage over white rice by offering protection from high blood
pressure and atherosclerosis (“hardening of the arteries”), report
researchers at the Cardiovascular Research Center and
Department of Physiology at Temple University School of Medicine
in Philadelphia.
Their new research suggests that a component in a layer of tissue
surrounding grains of brown rice may work against angiotensin II.
Angiotensin II is an endocrine protein and a known culprit in the
development of high blood pressure and atherosclerosis.
The research team is also composed of scientists from the Department
of Pathology, School of Medicine, Wakayana Medical University,
Wakayama, Japan; Department of Materials Engineering, Nagaoka
National College of Technology, Nagaoka, Japan.
The Effect of Brown Rice on Angiotensin II
The subaleurone layer of Japanese rice, which is located between the
white center of the grain and the brown fibrous outer layer, is rich in
oligosaccharides and dietary fibers, making it particularly nutritious.
However, when brown rice is polished to make white rice, the
subaleurone layer is stripped away and the rice loses some of its nutrients.
The subaleurone layer can be preserved in half-milled (Haigamai) rice or
incompletely-milled (Kinmemai) rice. These types of rice are popular in
Japan because many people there believe they are healthier than white rice.
The Temple team and their colleagues wanted to study the subaleurone
layer and proving the benefitsfor leaving it intact when rice is processed.
Because angiotensin II is a known factor in such lethal cardiovascular
diseases, the team chose to focus on learning whether the subaleurone
layer could somehow inhibit the dangerous protein before it does damage.
First, the team removed the subaleurone tissue from Kinmemai rice.
Then they separated the tissue’s components by exposing the tissue to
extractions of various chemicals such as ethanol, methanol and ethyl acetate.
The team then observed how the tissue affected cultures of vascular smooth
muscle cells. Vascular smooth muscle cells are an integral part of blood vessel
walls and are direct victims of high blood pressure and atherosclerosis.
During their analysis, the team found that subaleurone components inhibited
angiotensin II activity in the cultured vascular smooth muscle cells. This finding
suggests that the subaleurone layer of rice offers protection against high blood
pressure and atherosclerosis. It could also help explain why fewer people die
of cardiovascular disease in Japan, where most people eat at least one
rice-based dish per day, than in the U.S. where rice is not typically a primary
component of daily nutrition.
“Our research suggests that there is a potential ingredient in rice that may
be a good starting point for looking into preventive medicine for cardiovascular
diseases,” explained the researchers “We hope to present an additional health
benefit of consuming half-milled or brown rice [as opposed to white rice] as part
of a regular diet.”
Source:
Federation of American Societies for Experimental Biology
| |