rice bran lowers blood pressure in rats

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..... adding rice bran to the diets of hypertensive, stroke-prone rats

lowered the animals' systolic blood pressure by about 20 percent and,

via the same mechanism, inhibited angiotensin-1 converting enzyme, or ACE.

FOR IMMEDIATE RELEASE | March 02, 2006

How nice, brown rice: Study shows rice bran lowers blood pressure in rats

Contact: Bernstein

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Thousands of years ago, humans began scrubbing off and discarding the

outer layer of long-grain rice, preferring the polished white kernel

beneath. Now, for the first time, scientists in Japan have shown that

this waste product of rice processing, called rice bran, significantly

lowers blood pressure in rats whose hypertension resembles that of humans.

The team reports their findings in the March 8 issue of the Journal of

Agricultural and Food Chemistry, published by the American Chemical

Society, the world's largest scientific society.

A commonly prescribed class of drugs called ACE inhibitors dilates the

arteries of hypertensive patients and thus decreases their risk of

stroke, heart attack and kidney disease. But the drugs can also carry

side effects: chronic cough, allergic reactions, dizziness, even

kidney problems.

What if some component of our diet could work in similar fashion, with

few or no side effects? Researchers at Tohoku University and Japan's

National Research Institute of Brewing demonstrated that adding rice

bran to the diets of hypertensive, stroke-prone rats lowered the

animals' systolic blood pressure by about 20 percent and, via the same

mechanism, inhibited angiotensin-1 converting enzyme, or ACE.

" There's much work being done on various bran fractions to nail down

any health benefits, " says the journal's editor, Seiber, Ph.D.,

who is also director of the U.S. Department of Agriculture's Western

Regional Research Center in , Calif. " This particular paper

caught my attention for two reasons: the potential of bringing a waste

product like rice bran into beneficial use, and the way the group went

about their study with good controlled experiments using an

appropriate model. "

It's still not clear whether simply eating more brown rice, which

retains some of its bran, would reduce the risk of heart disease.

However, previous research in humans, as well as animals with high

cholesterol, does suggest that certain fractions of rice bran can

lower levels of unhealthy LDL cholesterol.

The Tohoku study adds antihypertensive activity to the picture, along

with a host of other biochemical markers that track blood glucose

(implicated in diabetes), lipid profile, kidney function and the

harmful effects of free radicals.

For example, high levels of a marker called 8-OHdG indicate biological

stress and genetic damage due to oxygen-based free radicals. The

researchers found that rice bran, which contains various forms of the

antioxidant Vitamin E, markedly lowered the rats' levels of the

peptide 8-OHdG.

" Oxidative stress plays an important role in the initiation and

progression of cardiovascular diseases, " explained lead author

Ardiansyah [editor note: name is correct as written, there is no first

name], a Ph.D. candidate at the university's School of Agricultural

Science.

He added one more element to the research that is new: using enzymes

to clip components of rice bran from its cell walls, rather than

extracting a fraction with ethanol. " I think enzymatic treatment will

be more suitable for applications if we'd like to use [rice bran as]

functional food, " he said.

The researchers' next step is to elucidate the mechanisms by which

specific components of rice bran inhibit ACE and lower cholesterol.

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