1. Rice Bran
Pennington Biomedical Research Center Division of Education Heli J. Roy PhD Shanna Lundy, BS Phillip Brantley, PhD, Director

2. Rice Bran Contents
Rice bran is composed of the aleurone layer of the rice kernel and some part of the endosperm and germ, which are rich sources of proteins, lipids, vitamins, and trace minerals
Rice bran’s oil and unsaponifiable lipid content is high compared with other grains
Unrefined rice bran oil consists of ~20% saturated, 40% monounsaturated, and 40% polyunsaturated fatty acids and contains tocotrienols, γ-oryzanol, and β-sitosterol
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3. Rice bran and its oil contain large concentrations of several compounds that could potentially prevent chronic diseases such as coronary heart disease and cancer
The LSU AgCenter has been actively identifying, extracting, purifying, and evaluating the functionality of several of these compounds
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4. Their initial studies with rice bran focused on stabilizing against lipid degradation that leads to flavor problems
During these studies, it was noted that rice bran contained high levels of both tocopherols and tocotrienols, which compromise vitamin E and act as antioxidants in the body
Also, high levels of a mixture of compounds referred to collectively as oryzanol were identified within rice bran
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5. Oryzanol components are complex compounds that can act as an antioxidant, improving solubility in cell membranes and potentially lowering cholesterol by competitive inhibition of absorption and synthesis
Methods of separating the individual components of the oryzanol mixture have come about, leading to the identification of 3 major fractions of oryzanol:
Cycloartenyl ferulate
24-methylene cycloartanyl ferulate
Campesteryl ferulate
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6. Because the causes associated with almost all chronic disease can be traced to the effects of oxidants, both in the environment and in our bodies, interest arose in the area of rice bran and its antioxidant capacity
Specifically, cholesterol oxidation products have been suggested as a major cause of heart disease
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7. Rice bran components do reduce cholesterol oxidation
The antioxidant activities of four of the vitamin E and three oryzanol components purified from rice bran were investigated in a chemical model of cholesterol oxidation
All components exhibited significant antioxidant capacity in the inhibition of cholesterol oxidation!
All three oryzanol components were higher than any of the four vitamin E components
Found that :
PBRC 2005

8. Rice bran & Osteoporosis
Osteoporosis affects more than 20 million older Americans, with the number increasing every year
Because of the risk for cancer associated with hormone replacement therapy in women, alternative methods to reduce bone loss are currently being investigated
Studies on rice bran and its role in osteoporosis have been conducted
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9. Ovariectomized rats (who typically lose substantial bone mineral density after the ovariectomy) were used as a model for postmenopausal osteoporosis
Found that with the addition of a 7% oryzanol rice bran oil (RBO) concentrate to the diets of these rats that reductions in bone loss at several bone sites occurred
The beneficial effect of the RBO concentrate appeared to be primarily on cortical bone in the long bones, and not on the trabecular bone in vertebrae
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10. Crystalline oryzanol and crystalline oryzanol dissolved in corn oil had no effect on bone mineral density
Suggesting that either the oryzanol as it occurs naturally in rice bran oil is more biologically active than crystalline oryzanol or that something else in the rice bran oil is affecting bone density positively
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11. More studies are needed to identify the active elements in rice bran oil beneficial in reducing bone loss and in determining their mode of action
Rice bran oil concentrate appears to primarily act on preserving the slow turn-over cortical bone in the long bones
Other functional foods, such as soy protein, act on rapid turnover trabecular bone in vertebrae
The possibility of using the two together in combination is an area currently under investigation
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12. More on Rice Bran…
In the past, human consumption of rice bran has been limited, primarily because of the rapid onset of rancidity in rice bran, but methods to stabilize rice bran and to extract its oils have been developed
Interest in rice bran grew from the determination that the inclusion of oat bran in the diet lowers serum cholesterol
Rice bran contains less total dietary fiber and less soluble fiber than oat bran
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13. Studies of Rice Bran ..
Based on its soluble fiber content alone, rice bran should have less hypolipidemic effects than other sources of fiber
However, studies of rice bran supplementation in humans found similar beneficial effects on lipoproteins
In a 10-week controlled feeding trial, rice bran was as effective as oat in lowering blood cholesterol concentrations in men and women with moderately high blood cholesterol concentrations
Has shown reductions in cholesterol levels in pigs, hamsters, rats, humans, and nonhuman primates
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14. Possible suggestions have included:
What exact component found in rice bran is responsible for its cholesterol-lowering effects?
Possible suggestions have included:
The fiber that is present
The Fatty acid composition
Or the Unsaponifiables present
Oryzanol, phytosterols (campesterol and β-sitosterol)
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15. Evidence from 2 well-controlled studies at Pennington Biomedical Research Center confirms that it is the rice bran oil (RBO), and not the fiber, that lowers blood lipids in men and women with borderline high total cholesterol
Although RBO does contain about 20% saturated fatty acids and approximately equal amounts of oleic and linoleic fatty acids, its’ cholesterol lowering ability is due to its unsaponifiable components more so than by its fatty acid composition
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16. In a recent study, by matching the fatty acids of the rice bran oil with a control oil blend, it was shown that the effect of RBO on serum cholesterol concentrations is due to the unsaponifiables present in it and not to its fatty acid profile
It is believed that RBO containing these compounds could become an important functional food with cardiovascular health benefits
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17. References
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