Rice Bran Health Benefits-Research

Ann Nutr Metab. 2009 Dec 15;56(1):45-51. [Epub ahead of print]

Ameliorative Effects of Stabilized Rice Bran on Type 2 Diabetes Patients.

Cheng HH, Huang HY, Chen YY, Huang CL, Chang CJ, Chen HL, Lai MH.

School of Nutrition and Health Science, Taipei Medical University,Taipei, Taiwan, ROC.

Background/Aim: While it has been demonstrated that rice bran might lower the cholesterol level in hypercholesterolemic individuals, its effects on the levels of adiponectin and glycated hemoglobin (HbA1c) in patients with type 2 diabetes mellitus remain unknown. Methods: Twenty-eight volunteers with type 2 diabetes were randomly divided into 2 groups, one of which received a dietary supplement of 20 g of stabilized rice bran and the other placebo once daily for 12 weeks. Parameters such as the level of HbA1c, glucose, insulin, homeostasis model assessment for estimation of relative insulin resistance, high-density and low-density lipoprotein (LDL) cholesterol and adiponectin were evaluated. Results: At the end of the study period, postprandial glucose and the area under the glucose curve of the rice bran group were significantly lower than baseline levels by 14.4 and 15.7%, respectively. Compared to baseline, the HbA1c values in the rice bran group were also significantly lower. Serum total cholesterol and LDL cholesterol concentrations in the rice bran group were 9.2 and 13.7% lower, respectively, than in the placebo group. The plasma free fatty acid and adiponectin concentrations were 20% lower and 40% higher in the rice bran group compared to the placebo group. Conclusions: This study demonstrated that stabilized rice bran can lower the level of HbA1c and blood lipids and increase blood adiponectin concentrations in type 2 diabetic subjects. In light of this, we conclude that stabilized rice bran may represent an important functional nutrient to ameliorate lipid and glycemic anomalies in type 2 diabetic subjects. Copyright © 2009 S. Karger AG, Basel.

J Med Food. 2009 Jun;12(3):615-23.

Pro-inflammatory enzymes, cyclooxygenase 1, cyclooxygenase 2, and 5-lipooxygenase, inhibited by stabilized rice bran extracts.

Roschek B Jr, Fink RC, Li D, McMichael M, Tower CM, Smith RD, Alberte RS.

HerbalScience Group LLC, Naples, Florida 34110, USA.

Rice bran, the outer bran and germ of the kernel and a by-product of rice milling, is rich in phytonutrients but has been underutilized because of lipid content instability. New methods for the processing of rice bran have yielded a stabilized form that is increasingly used in foods and dietary supplements. Recent studies have documented a role for stabilized rice bran (SRB) in treating diabetes and arthritis, although little is known of the bioactive compounds that impart these health benefits. Here we characterize the chemical composition of three extracts of SRB and identify the functional bioactives contributing to the inhibitory properties against three key pro-inflammatory enzymes (cyclooxygenase [COX] 1, COX2, and 5-lipoxygenase [5-LOX]) that control the inflammatory cascade involved in impaired joint health, pain, and arthritis. One extract (SRB-AI) demonstrated significant COX1 and COX2 inhibitory activities with 50% inhibitory concentration (IC(50)) values for COX1 and COX2 of 305 and 29 microg/mL, respectively, but no 5-LOX inhibition. The second extract (SRB-AII) inhibited COX1, COX2, and 5-LOX with IC(50) values of 310, 19, and 396 microg/mL, respectively. The third extract (SRB-AIII), a blend of SRB-AI and SRB-AIII, inhibited COX1, COX2, and 5-LOX with respective IC(50) values of 48, 11, and 197 microg/mL. Analysis of the extracts by direct analysis in real time time of flight-mass spectrometry revealed that SRB-AI, SRB-AII, and SRB-AIII contain over 620, 770, and 810 compounds, respectively. Of these, 17 were identified as key bioactives for COX and/or LOX inhibition. These SRB extracts have applications for functional foods and dietary supplements for control of inflammation and joint health.

 

J Nutr Biochem. 2002 Mar;13(3):175-187.

Effects of stabilized rice bran, its soluble and fiber fractions on blood glucose levels and serum lipid parameters in humans with diabetes mellitus Types I and II.

Qureshi AA, Sami SA, Khan FA.

Advanced Medical Research, 8251 Raymond Road, 53719, Madison, WI, USA

Stabilized rice bran (SRB), a source of complex carbohydrates, tocols, gamma-oryzanols, and polyphenols, was treated with carbohydrases and heat to yield two fractions, rice bran water solubles (RBWS), and rice bran fiber concentrates (RBFC). Stabilized rice bran and its fractions were fed for 60 days to insulin-dependent and noninsulin-dependent diabetes mellitus (IDDM = Type I and NIDDM = Type II) subjects to determine possible effects on serum hemoglobin, carbohydrate and lipid parameters. The Type I subjects (n = 22, 26, and 20) fed Stabilized rice bran, rice bran water solubles, and rice bran fiber concentrates plus AHA Step-1 diet reduced glycosylated hemoglobin 1%, 11%, and 10%, respectively. The fasting serum glucose levels were also reduced significantly (P < 0.01) with stabilized rice bran (9%), rice bran water solubles (29%), and rice bran fiber concentrates (19%).The Type II subjects (n = 31, and 26) fed rice bran water solubles and rice bran fiber concentrates plus AHA Step-1 diet had decreased levels of glycosylated hemoglobin (15% and 11%) and fasting glucose (33% and 22%; P < 0.001), respectively. Serum insulin levels were increased (4%) with rice bran water solubles in both types of diabetes. The reduction of glycosylated hemoglobin and a slight increase in insulin levels indicate that consumption of rice bran water solubles can control blood glucose levels in human diabetes. Serum total cholesterol, LDL-cholesterol, apolipoprotein B, and triglycerides levels were reduced with rice bran fiber concentrates in the Type I (10, 16, 10, 7%) and Type II groups (12, 15, 10, 8%), respectively. These results indicate that rice bran water solubles significantly reduces hyperglycemia (P < 0.01), whereas rice bran fiber concentrates reduces hyperlipidemia (P < 0.05) in both types of diabetes. Therefore, these natural products can be used as nutritional supplements for the control of both types of diabetes mellitus in humans.

 

J Nutr. 1998 May;128(5):865-9.

Full-fat rice bran and oat bran similarly reduce hypercholesterolemia in humans.

Gerhardt AL, Gallo NB.

Department of Medicine, University of California, Davis Medical Center and Sutter Heart Institute, Sacramento, CA 95819, USA.

Scientific studies support recommendations to increase dietary soluble fiber as part of hyperlipidemia treatment. Rice bran contains minimal soluble fiber, but rice bran oil has a hypolipidemic effect. Full-fat rice bran was compared with oat bran and a rice starch placebo in hyperlipidemic humans to see if it might have a role in the treatment of hyperlipidemia. Moderately hypercholesterolemic (5.95-8.02 mmol/L), nonsmoking, nonobese adults were studied in a 6-wk, randomized, double-blind, noncross-over trial. Three groups added 84 g/d of a heat-stabilized, full-fat, medium-grain rice bran product (n = 14), oat bran product (n = 13) or rice starch placebo (n = 17) to their usual low-fat diet. Serum cholesterol, triglycerides, HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), apoA1 and apoB were measured before and at the end of the supplementation period. Serum cholesterol decreased significantly (P </= 0.05) by 8.3 +/- 2.4% and 13.0 +/- 1.8% in the rice bran and oat bran groups, respectively, but there was no change in the rice starch group. This change was attributable to LDL-C, which decreased by 13.7 +/- 2.8% in the rice bran group and 17.1 +/- 2.4% in the oat bran group (P </= 0.05). Serum apoB decreased proportionately. There was no consistent effect on triglycerides within each group and HDL-C and apoA concentrations did not change. The LDL-C:HDL-C ratio decreased significantly in the rice bran and oat bran groups. Stabilized, full-fat rice bran or oat bran, added to the prudent diet of hyperlipidemic adults, similarly reduced cholesterol and LDL-C and improved lipid ratios in 78% of these individuals. Rice bran, as well as oat bran, should be included in the prudent diet of individuals with hyperlipidemia.

Drugs Exp Clin Res. 2001;27(1):17-26.

Rice-bran products: phytonutrients with potential applications in preventive and clinical medicine.

Jariwalla RJ.

California Institute for Medical Research, San Jose, CA, USA.

This paper reviews phytonutrients from rice bran that have shown promising disease-preventing and health-related benefits in experimental research studies. Candidate products studied and under investigation include: inositol and related compounds, inositol hexaphosphate (IP6 or phytate), rice oil, ferulic acid, gamma-oryzanol, plant sterols, tocotrienols and RICEO, a new rice-bran-derived product. Diseases in which preventive and/or nutraceutical effects have been detected include: cancer, hyperlipidemia, fatty liver, hypercalciuria, kidney stones, and heart disease. In addition, rice-bran products may have potential applications as nutritional ingredients in the context of their utility in functional foods.