Rice bran solubles

Rice bran solubles are a nutritional product derived from the bran shavings produced as brown rice is converted into white rice. The shavings are usually discarded or used for animal feed.^[1] In Japan, they are used in some traditional pickling recipes.^[2] To produce rice bran solubles, the bran shavings are heat treated to prolong shelf-life and then enzymatically extracted to collect water-soluble components.^[3]

Rice bran solubles are used as a nutritional supplement. The supplement is sometimes called tocos because of its high content of tocopherols (vitamin E). Rice bran solubles contains about 15-40% fat, 0-25% dietary fiber, 0-15% protein, and 25-80% carbohydrates.^[4]

Concerns have been raised about the levels of arsenic in rice bran solubles.^[5][6] Rice naturally accumulates arsenic from the soil as it grows, with rice bran having higher levels than white rice.^[7] One study found that rice bran solubles contain even higher concentrations of arsenic.^[5] Consumption of products at the manufacturers recommended rate would provide 0.012-0.038 mg of arsenic, above the maximum level of 0.01 mg level considered safe.^[5]