Selenium exists in many foods, and the content is higher in aquatic products such as fish and shrimp, followed by the heart, kidney and liver of animals. The highest content of vegetables is cauliflower, shepherd's purse, garlic and mushroom, followed by peas, Chinese cabbage, pumpkin, radish, leek, onion, tomato and lettuce. Among them, the selenium content of animal kidney is four times that of liver, and the selenium content of liver is four times that of meat; Eggs contain more selenium than meat; Beef has the highest selenium content in lean meat. According to the survey data, the selenium content of natural foods is from high to low, and the general order is seafood, animal offal, fish, eggs, meat, grains, milk (powder), vegetables and fruits.
Generally speaking, the utilization rate of organic selenium in plants is high, up to 70%-90%, while the utilization rate of selenium in animal products is low, only about 50%. Although seafood and animal organs are rich in organic selenium, they are not ideal selenium supplement products. Because marine products contain methylmercury, which can combine with selenium to form inactive substances, resulting in low utilization rate of selenium; Animal organs contain more cholesterol, which is especially unfavorable to middle-aged and elderly people and patients with cardiovascular diseases. In addition, eating more fruits, vegetables and other foods rich in vitamins A, C and E will help to absorb selenium. China is a big country with selenium deficiency, and two-thirds of the areas are selenium-deficient areas. The relationship between the absorption rate of selenium in food and the content of selenium in soil is greater than that with diet. It is a quick and effective method to supplement selenium preparation in selenium-deficient areas.