Once upon a time, people regarded eating polished rice and white flour as a sign of rich life. However, when food and clothing is no longer a problem, people began to pursue brown rice again. This cycle reflects people's concern for health-people's concern for health is different under different economic conditions. Brown rice is the product of rice hulling. There is a layer of skin on the surface of brown rice, which contains a lot of fiber, so it affects the taste. Remove this fiber and get polished rice. The removed layer generally accounts for about 7% of the total weight of brown rice, which is called "rice bran". Although rice bran is not delicious, it contains dietary fiber, a lot of vitamins and minerals, and rich antioxidants. In addition, the oil content is not low. These oils are mainly unsaturated fats. Compared with animal oils, they are considered as "healthy" oils. Scientific data show that if saturated fat is replaced by unsaturated fat, such as animal fat, it will be of great benefit to cardiovascular health. So brown rice without rice bran is healthier than delicious polished rice. Those unpalatable rice bran, traditionally used as animal feed, have turned pheasants into phoenixes and become "treasures" for developing "health food".

There are many kinds of functional foods made from rice bran. In addition to directly adding rice bran into food to make functional food, the effective components in rice bran are also directly extracted as "health products"-usually called "rice bran extract". At present, this kind of products are developing vigorously in our country. It should be said that the ingredients claimed by these products may be true, and which ingredients are often beneficial to health. But in academic circles, there are always different voices about this kind of products. The biggest problem is inorganic arsenic. Brown rice is the product of rice husk removal, with a layer of skin on the surface and a lot of fiber, which affects the taste. Remove this fiber and get polished rice. The removed layer is rice bran, which generally accounts for about 7% of the total weight of brown rice. Although rice bran is not delicious, it contains dietary fiber, a lot of vitamins, minerals and rich antioxidants, which are lacking in modern people's diet. In addition, it also contains high content of oil. These oils are mainly unsaturated fats. Compared with animal oils, they are certainly "healthy" oils, which are quite beneficial to cardiovascular health.

Judging from the nutritional value, inferior brown rice is indeed healthier than high-quality polished rice. Therefore, rice bran, which was originally only used as animal feed, has become a treasure and has been developed into various "brown rice" health foods. There are many kinds of functional foods made from rice bran in Japan and China. However, there have been different "voices" in the academic evaluation of such products. The biggest difference lies in the inorganic arsenic in rice bran. Rice grows in water, so it is rich in arsenic. Arsenic is widely distributed on the earth and is inevitable in natural water. The arsenic content of different water quality is different. Rice is also the main source of arsenic intake for people who eat rice as their staple food. But arsenic is actually a semi-metallic element harmful to human body, especially inorganic arsenic, because its carcinogenicity has been confirmed, and it was once called "first-class carcinogen" by scientists. Tens of thousands of people in Bangladesh are poisoned by arsenic.

For the human body, the lower the arsenic intake, the better. The relevant "safety standard" formulated by the World Health Organization is that each person should not exceed 2 micrograms per kilogram per day-that is, people weighing 60 kilograms should not consume more than 0. 12 milligrams per day. What is the content of inorganic arsenic in rice? The measured values shown in academic literature are related to the origin and planting methods of rice. Relatively speaking, the rice content in China is not high. The standard of inorganic arsenic content in rice in China is not more than 0. 1.5 mg/kg. Considering that it is difficult for people to eat more than 800g of rice a day, this standard should be reasonable. In Europe and America, where rice consumption is low, there is actually no such regulation.

The arsenic content in polished rice is lower than that in brown rice, and the arsenic content in rice bran can reach more than 10 times of that of polished rice. Rice bran extract not only extracted "effective components", but also extracted arsenic naturally. In 2008, environmental science and technology published an article saying that the contents of inorganic arsenic in five kinds of rice bran extracts in the US and Japan markets were all 0.6 1- 1.9 mg/kg. This obviously exceeds the standard. "Rice bran extract" is the signboard of various "rice bran health products". The researchers said that the average merchant recommended that consumers eat about 20 grams a day, that is to say, the total amount of inorganic arsenic ingested from it was about 0.0 12-0.038 mg. Although this content does not exceed the "safety standard" stipulated by the World Health Organization, considering that people may ingest arsenic from other sources, this content is enough to attract people's attention. Of course, the arsenic content in brown rice is not much higher than that in polished rice. The vitamins, minerals and antioxidants in brown rice have positive effects on health. Eating brown rice or polished rice depends on how individuals weigh "benefits" and "risks".