Rice Bran Oil
Is It Healthy?
What is rice bran oil?
Rice bran oil refers to the oil extracted from the outer layer of rice grain, known as rice bran. This oil is commonly used as a cooking oil in many Asian countries, including China, India and Japan. Virtually all rice bran oil is refined as rice bran oil extraction is not possible without chemical solvents. Hence, it has a high smoke point of 232°C(450°F), mild flavor, neutral taste and long shelf life. This oil is popular in Asian cuisine, because of its suitability for high-temperature cooking methods such as stir- frying and deep-frying.
How rice bran oil is made?
Rice bran is a by-product of the rice milling industries and rice bran oil is extracted from the rice bran via several techniques. Solvent extraction using hexane is the most commonly used method for commercial extraction.
After collecting rice bran oil cake, rice bran oil is extracted with the help of chemical hexane. Then, the solvent is evaporated and the oil is pumped into refining machinery for refining process which includes degumming, neutralisation, decolorisation, deodorisation and dewaxing.
Majority of nutrients are lost during refining process. Hence, cold-pressed oil has more nutrients than refined oil. Among the benefits of cold-pressed rice bran oil are:
- Support heart health
Rice bran oil helps reduce total cholesterol and LDL (bad) cholesterol levels, and increase HDL (good) cholesterol levels1,2. Besides, it also helps increase antioxidant capacity in individuals with high blood lipid profile3. All these may lead to prevention and control of cardiovascular disease (CVD).
- Support healthy blood sugar
Rice bran oil may support healthy blood sugar levels by ameliorating insulin resistance, which is a risk factor for type 2 diabetes4. A human trial showed that the morning after 19 healthy men consumed a single meal supplemented with 3.7g of rice bran mixed in oil, their blood sugar levels decreased 15%, compared to placebo-supplemented meal5. Besides, an animal test also demonstrated that rice bran oil significantly lowered blood sugar levels in mice with type 2 diabetes, by increasing insulin levels, compared with the control group6.
Provide anti-inflammatory effects
Rice bran oil contains several anti-inflammatory compounds. One of them is γ-Oryzanol, which suppresses several enzymes that promote inflammation7. Another active component in rice bran oil, known as δ-Tocotrienol, also suppresses inflammation8.
During the refining process, rice bran oil may lose some of the important nutrients that have health-promoting effects. This lowers its nutritive value, causing it to be less healthy than other unrefined cooking oils. A study shows that 10-36% of total tocopherols (Vitamin E), 6-52% of total sterols and 93-98% polyphenols are lost during refining process of vegetable oils9. Another study showed that after refining, the amount of oryzanol left in rice bran oil is small, which is unlikely to provide beneficial effects on the healths10,11. Nonetheless, refined rice bran oil has high smoke point and neutral taste, making it a good choice for stir-frying and deep-frying.
- Heavy metal content
In recent years, concerns have surfaced over high arsenic content in rice bran oil. When rice is grown in flooded fields, it absorbs around 10 times as much arsenic as normal. Most of the arsenic concentrates in the bran and a study has suggested that rice bran contains high levels of arsenic12.
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10. Journal of the American Oil Chemists’ Society. 2001. 78(2): 127-131.
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12. Environ Sci Technol.2008 Oct 1;42(19): 7542-6.