Flow of Selenium in the “Soil-Crop-Food-Human” Chain

Selenium (Se) is an indispensable micronutrient in the human body, which participates in various physiological and metabolic processes. Around the world, about 500 million to 1 billion people are at risk from selenium deficiency related diseases. In the agriculture-food system, selenium enters the food chain mainly from soil, and is accumulated in crops and then assimilated by the human body through diets. Using suitable agronomic measures to enhance the ability of crops to absorb and transform soil selenium can enable organic selenium to effectively accumulate in the edible parts of crops. However, the enrichment of selenium in crops does not mean that selenium can be completely retained in crop foods. The influence of food processing is extremely critical as well. Various processing conditions and parameters will affect the selenium content and speciation of the final products, thus affecting its bioavailability in the human body. This paper reviews the flow of selenium in the “soil-crop-food-human” chain, and summarizes the key factors that affect the content and speciation of selenium in foods and the bioavailability of selenium in the human body. It is suggested that all factors should be considered comprehensively to realize efficient conversion of selenium from farm to table.