Abstract
Selenium (Se) is an essential trace element in human nutrition. In this review, contents, chemical species and nutritional availability of Se in foods and Se intake in Japanese are discussed. Most fish meats showed high Se values (> 0.3 μg/g) . Se contents in cereal and beans are varied dependently to soil Se contents; high Se contents are observed in wheat and soybeans grown on a central area of North American Continent. Since Japan imports a large amount of wheat and soybean, most of bread, pasta and natto sold in Japan show high Se contents (> 0.1 μg/g) . In addition, north American cereals and beans are used as materials for feed of livestock, meats and eggs also show high Se (> 0.1 μg/g) in Japan. Se intake of Japanese is estimated to be about 100 μg/d which is comparatively high among the world. Se species in cereals and beans with a normal range of Se (< 0.5 μg/g) and that in Se-enriched yeast are protein-bound selenomethionine, while a part of Se species in fish meat is believed to be selenocysteine. Most Se-enriched vegetables contains Se-methylselenocysteine as a major Se species and a part of Se-enriched vegetables contain selenohomolanthionine and γ-glutamyl-Se-methylselenocysteine. Nutritional availability of Se in foods is able to be estimated by a slope ratio analysis. The availability of Se in Se-enriched yeast is high, but those in Se-enriched radish sprouts and in processed skipjack meats are low.
