Compendium of the most significant studies with reference to properties, intake, effects.

Most MM, Tulley R, Morales S, Lefevre M. Rice bran oil, not fiber, lowers cholesterol in humans. Am J Clin Nutr. 2005 Jan;81(1):64-8. doi: 10.1093/ajcn/81.1.64. 

Abstract. Background: The cholesterol-lowering abilities of rice bran's fiber and oil apart from its fatty acid composition remain unclear. Objective: The objective of the study was to assess the effects of defatted rice bran and rice bran oil in an average American diet on blood lipids in moderately hypercholesterolemic persons....Conclusions: Rice bran oil, not fiber, lowers cholesterol in healthy, moderately hypercholesterolemic adults. There were no substantial differences in the fatty acid composition of the diets; therefore, the reduction of cholesterol was due to other components present in the rice bran oil, such as unsaponifiable compounds.

Lichtenstein AH, Ausman LM, Carrasco W, Gualtieri LJ, Jenner JL, Ordovas JM, Nicolosi RJ, Goldin BR, Schaefer EJ. Rice bran oil consumption and plasma lipid levels in moderately hypercholesterolemic humans. Arterioscler Thromb. 1994 Apr;14(4):549-56. doi: 10.1161/01.atv.14.4.549.

Abstract. The effect of rice bran oil, and oil not commonly consumed in the United States, on plasma lipid and apolipoprotein concentrations was studied within the context of a National Cholesterol Education Panel (NCEP) Step 2 diet and compared with the effects of canola, corn, and olive oils. The study subjects were 15 middle-aged and elderly subjects (8 postmenopausal women and 7 men; age range, 44 to 78 years) with elevated low-density lipoprotein (LDL) cholesterol (C) concentrations (range, 133 to 219 mg/dL). 

Amended final report on the safety assessment of Oryza Sativa (rice) Bran Oil, Oryza Sativa (rice) Germ Oil, Rice Bran Acid,Oryza Sativa (rice) Bran Wax, Hydrogenated Rice Bran Wax, Oryza Sativa (rice)Bran Extract, Oryza Sativa (rice) Extract, Oryza Sativa (rice) Germ Powder, Oryza Sativa (rice) Starch, Oryza Sativa (rice) Bran, Hydrolyzed Rice Bran Extract, Hydrolyzed Rice Bran Protein, Hydrolyzed Rice Extract, and Hydrolyzed Rice Protein. Int J Toxicol. 2006;25 Suppl 2:91-120. doi: 10.1080/10915810600964626.

Abstract. This report addresses the safety of cosmetic ingredients derived from rice, Oryza sativa. Oils, Fatty Acids, and Waxes: Rice Bran Oil functions in cosmetics as a conditioning agent--occlusive in 39 formulations across a wide range of product types. Rice Germ Oil is a skin-conditioning agent--occlusive in six formulations in only four product categories. Rice Bran Acid is described as a surfactant-cleansing agent, but was not in current use. Rice Bran Wax is a skin-conditioning agent--occlusive in eight formulations in five product categories. Industry did not directly report any use of Rice Bran Wax. Hydrogenated Rice Bran Wax is a binder, skin-conditioning agent--occlusive, and viscosity-increasing agent--nonaqueous in 11 formulations in six product categories. Rice Bran Oil had an oral LD50 of > 5 g/kg in white rats and Rice Wax had an oral LD50 of > 24 g/kg in male mice. A three-generation oral dosing study reported no toxic or teratologic effects in albino rats fed 10% Rice Bran Oil compared to a control group fed Peanut Oil. Undiluted Rice Bran Oil, Rice Germ Oil, and Hydrogenated Rice Bran Wax were not irritants in animal skin tests. Rice Bran Oil was not a sensitizer. Rice Bran Oil, Rice Germ Oil, Rice Wax, and Hydrogenated Rice Bran Wax were negative in ocular toxicity assays. A mixture of Rice Bran Oil and Rice Germ Oil had a ultraviolet (UV) absorption maximum at 315 nm, but was not phototoxic in a dermal exposure assay. Rice Bran Oil was negative in an Ames assay, and a component, gamma-oryzanol, was negative in bacterial and mammalian mutagenicity assays. Rice oils, fatty acids, and waxes were, at most, mildly irritating in clinical studies. Extracts: Rice Bran Extract is used in six formulations in four product categories. Rice Extract is a hair-conditioning agent, but was not in current use. Hydrolyzed Rice Extract is used in four formulations and current concentration of use data were provided for other uses. Hydrolyzed Rice Bran Extract, described as a skin-conditioning agent--miscellaneous, is used in two product categories. Use concentrations are in the 1% to 2% range. Rice Bran Extract is comprised of proteins, lipids, carbohydrates, mineral ash, and water. The content includes palmitic, stearic, oleic, and linoleic acids. Other components include antioxidants such as tocopherols. Rice Extract reduced the cytotoxicity of sodium chloride in male rats. Bran, Starch and Powder: Rice Bran (identified as rice hulls) is an abrasive and bulking agent in one formulation. Rice Starch is an absorbent and bulking agent in 51 formulations across a wide range of product categories. Rice Germ Powder is an abrasive and one manufacturer described an exfoliant use, but it was not reported to be used in 2002. Oral carcinogenicity studies done on components of Rice Bran (phytic acid and gamma-oryzanol) were negative. Rice Bran did not have an anticarcinogenic effect on 1,2-dimethylhydrazine-induced large bowel tumors. In cocarcinogenicity studies done using 1,2-dimethylhydrazine and other agents, with Rice Bran Oil and Rice Bran-derived hemicellulose and saccharide, tumor inhibition was observed; gamma-oryzanol did not inhibit the development of neoplasms. A decrease in cutaneous lesions in atopic dermatitis patients was reported following bathing with a Rice Bran preparation. Proteins: Hydrolyzed Rice Bran Protein and Hydrolyzed Rice Protein function as conditioning agents (hair or skin), but only the latter was reported to be used in a few products. An in vitro phototoxicity assay using UVA light found no photochemical toxicity. Rice bran protein hydrolysates are not acutely toxic, are not skin or ocular irritants in animals, are not skin sensitizers in guinea pig maximization tests, and are not irritating or sensitizing in clinical tests. Isolated cases of allergy to raw rice have been reported, but rice, in general, is considered non allergenic. The Cosmetic Ingredient Review (CIR) Expert Panel considered that safety test data available on certain of these ingredients could be extrapolated to the entire group. Although Rice Bran Extract does contain UV absorbing compounds at low concentrations, clinical experience suggested no phototoxicity would be associated with such materials. Rice derived ingredients generally are considered to be non allergenic. There were no safety test data available for Hydrolyzed Rice Extract and Hydrolyzed Rice Bran Extract, but their safety may be inferred from that of the extracts from which they are derived. Current levels of polychlorinated biphenyls (PCBs) and heavy metals in rice-derived ingredients used in cosmetics are not a safety concern. The Panel was concerned, however, that contaminants such as pesticides have been reported in Rice Bran Oil used for cooking. Pesticides and heavy metals should not exceed currently reported levels for rice-derived cosmetic ingredients. The CIR Expert Panel concluded that these rice-derived ingredients are safe as cosmetic ingredients in the practices of use and concentrations as described in this safety assessment.

Salem EG, El Hissewy A, Agamy NF, Abd El Barry D. Assessment of the quality of bran and bran oil produced from some Egyptian rice varieties. J Egypt Public Health Assoc. 2014 Apr;89(1):29-34. doi: 10.1097/01.EPX.0000443988.38424.9d.

Abstract. Background: Rice (Oryza sativa L.) is one of the leading food crops of the world, the staple food of over half the world's population. The bran, which is an important byproduct obtained during rice milling, constitutes about 1/10 of the weight of the rice grain. Rice bran is the outer brown layer including the rice germ that is removed during the milling process of brown grain. This milling byproduct is reported to be high in natural vitamins and minerals, particularly vitamin E..Objectives: The present study was conducted to determine the chemical composition of bran and bran oil of 13 different rice varieties commonly produced in Egypt, to study the utilization of rice bran in bread production, and to assess the quality and acceptance of the rice bran edible oil produced....Conclusion: Rice bran contains high nutritional components as well as phytochemicals such as vitamin E (i.e. tocopherols and tocotrienols) and the γ-oryzanol fraction that have positive effects on human health. Storage of paddy rice before milling resulted in significant effect on all studied rice bran characters and rice bran oil characters under the present investigation except crude protein and carbohydrates characters.

Sohail M, Rakha A, Butt MS, Iqbal MJ, Rashid S. Rice bran nutraceutics: A comprehensive review. Crit Rev Food Sci Nutr. 2017 Nov 22;57(17):3771-3780. doi: 10.1080/10408398.2016.

Abstract. Agro-industry yields ample quantity of several byproducts with considerable importance. These byproducts are mostly under-utilized, often used as animal feed or rejected as waste; hence their true potential is not harnessed. The use of such superfluous resources is of not only economic significance but also a form of commercial recycling. Rice bran is an important byproduct of rice milling industry with a global potential of 29.3 million tons annually. It is gaining great attention of the researchers due to its nutrient-rich composition, easy availability, low cost, high antioxidant potential, and promising effects against several metabolic ailments. Bioactive components of rice bran, mainly γ-oryzanol, have been reported to possess antioxidant, anti-inflammatory, hypocholesterolemic, anti-diabetic, and anti-cancer activities. Rice bran oil contains appreciable quantities of bioactive components and has attained the status of "Heart oil" due to its cardiac-friendly chemical profile. Nutraceutics have successfully been extracted from rice bran using several extraction techniques such as solvent extraction, supercritical fluid extraction, microwave-, and ultrasonic-assisted extraction. Current paper is an attempt to highlight bioactive moieties of rice bran along with their extraction technologies and health benefits.

Behl T, Kumar S, Sehgal A, Singh S, Kumari S, Brisc MC, Munteanu MA, Brisc C, Buhas CL, Judea-Pusta C, Buhas CL, Judea-Pusta C, Nistor-Cseppento DC, Bungau S. Rice bran, an off-shoot to newer therapeutics in neurological disorders. Biomed Pharmacother. 2021 Aug;140:111796. doi: 10.1016/j.biopha.2021.111796.

Abstract. ...This review covers the neuroprotective multiplicity of rice bran and its constituents to deter pathological conditions of the brain and to facilitate balanced brain functioning at the same time. Copyright © 2021. Published by Elsevier Masson SAS.