5 Health Benefits of Rice Bran Oil

Rice is the staple food for more than half of the people of the world. The crop is grown in more than 100 countries. Out of the total produce of rice, 85% is used for human consumption and 15% is used as animal feed or is left to waste. Rice is eaten in the form of the polished, white grain. However, the process of refining rice (removal of bran) causes the loss of many nutrients.

Rice bran oil is a coproduct of milled rice. It is used in Japan, Korea, China, Taiwan, and Thailand as a premium edible oil. The oil is popularly called “heart oil” in Japan.

Composition of rice bran oil

Rice bran oil is composed of triglycerides (80%) and minor constituents such as phospholipids (2%), glycolipids (1%), sterols (5%), and waxes (2-5%). The fatty acids present in rice bran oil are myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and arachidic acid.

Unsaponifiable matter in rice bran oil consists of 42% sterols, 24% higher alcohols, 20% ferulic acid esters, 10% hydrocarbons, and 2% unknown components.

• Beta-sitosterol is the most abundant sterol present.
• Oryzanol, a ferulic acid ester, is said to have properties similar to vitamin E.

Depending on the method of extraction and the origin of the bran, wax comprises 3-9% of rice bran oil.

High quantities of tocopherols (0.1%) are present in rice bran oil – alpha tocopherol, alpha tocotrienol, and gamma tocotrienol.

Health benefits of rice bran oil

1. Lowers cholesterol levels. Due to the presence of large amounts of phytosterols, oryzanols, and tocotrienols present in rice bran oil, it has the property of lowering cholesterol levels. According to a study published in the journal Food and Chemical Toxicology in 2005, the total cholesterol levels in rats fed with the tocotrienol-rich fraction of rice bran oil reduced by 42% and the low-density lipoprotein levels reduced up to 62%.  

2. Shows anti-cancer activity. According to a study published in the journal Advances in Nutrition in 2012, phytochemicals present in rice bran such as tricin, beta-sitosterol, ferulic acid, gamma-oryzanol, tocotrienols/tocopherols, and phytic acid give it is chemopreventative properties. These phytochemicals suppress cell proliferation, promote apoptosis, and change the progression of the cell cycle.

3. Exhibits anti-ageing property. The bioactive components of rice bran oil protect tissues against damage by free radicals by capturing them. Thus, they block chronic inflammatory responses. Oryzanol protects against UV-induced lipid peroxidation. Thus, it acts as a sunscreen agent.

Tocotrienols present in rice bran oil are easily absorbed by the skin (when applied topically) and accumulate in the strata corneum. Thus, it has an antioxidant effect by protecting against UV-induced damage and ageing of skin.

4. Decreases risk of type 2 diabetes. A study published in the Journal of Nutrition in 2006 reported that feeding diabetic rats a diet containing rice bran oil reduced the levels of plasma triglyceride, LDL cholesterol, and hepatic triglycerides. Gamma-oryzanol and gamma-tocotrienol causes increased fecal neutral sterol and bile acid excretion.

5. Other benefits. The gamma-oryzanol content of rice bran oil reduces raised serum levels in people with hypothyroidism. It is used as a performance-enhancing supplement by athletes and body builders. It reduces bone loss in women with post-menopausal osteoporosis.

Although rice bran is rich in nutrients, it has been underutilized, partly due to ignorance, and partly due to the presence of impurities like silica and arsenic as well as the difficulties due to presence of free fatty acids. Advanced technologies present today such as super critical fluid extraction can be used to produce neutraceuticals that are effective against coronary heart disease.

References:

Nicolosi, R. J., Rogers, E. J., Ausman, L. M., & Orthoefer, F. T. (1994). Rice bran oil and its health benefits. Rice science and technology, 59, 421e437.

Most, M. M., Tulley, R., Morales, S., & Lefevre, M. (2005). Rice bran oil, not fiber, lowers cholesterol in humans. The American journal of clinical nutrition,81(1), 64-68.

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