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