Molecular species of selenium contained in general foods

Abstract

This short review describes the molecular species of selenium that the Japanese intaked from general foods. Before the widespread use of HPLC-ICPMS as a means of identifying selenium molecular species, selenomethionine was known to be the selenium molecular species in both high-selenium wheat and soybean protein. After the dissemina- tion of HPLC-ICPMS, Se-methylselenocysteine, γ-glutamyl-Se-methylselenocysteine, and selenohomolanthionine in sele- nium-exposed plants, selenosugar, trimethylselenonium, and selenocyanate in animal urine and tissues, and selenoneine in dark muscle of tuna were identified. The authors analyzed protease hydrolysates of general fish, shellfish, and meat by HPLC-ICPMS and confirmed that selenomethionine was the selenium molecule species in fish and shellfish, and selenomethionine and selenocystine in meat. In summary, the selenium molecular species in cereals, soybeans, and seafood, which are the major sources of selenium in Japanese people, are mostly selenomethionine, while sele- nomethionine and selenocystine are the selenium molecular species in meat. It is considered that selenomethionine accounts for nearly 90% of the selenium intaked by the Japanese, with selenocystine making up the remainder.