The objective of the ten years' study was to track the transfer of selenium in the food chains of animals and humans. The selenium content of the flora varies significantly with the geological origin of the soil, its pH, plant species, plant age, and the protein content of the plant parts eaten. In Central Europe, the flora on the usually neutral loess soils is seleniumrich, whereas the acidic soils formed by the weathering of gneiss, slate, granite, phyllite and Bunter as well as diluvial sands, bear a selenium-poor vegetation. The bioavailability of soil selenium increases significantly with pH. From 1988 until the end of the millenium, the selenium content of vegetable foods was studied systematically in 75 food types and 1035 samples. It was found that, with few exceptions, vegetable foods are generally poor in selenium. This applies in particular to all foods rich in starch and sugar. Protein-rich leguminosae, cruciferes rich in glucosinolate (mustard, caraway, cabbages) and especially such vegetable species that are eaten in a very young state (asparagus, mushrooms) supply plenty of selenium to the food chain. Since selenium was added to mineral feed mixtures for farm animals, animal foods (47 types with 597 samples) proved generally rich in selenium. This applies in particular to offal (kidneys, liver), hens' eggs and various species of sea fish which on average contain 500 to 9000mg Se/kg of dry matter. Beverages (with the exception of egg-liqueur) hardly contribute to the selenium supply. Animal foods supply 69 and 75% of the selenium demand of women and men, respectively. The figures for vegetable foods are 30 and 23%, respectively. People living by a mixed diet get most of their selenium from animal foods.
Ernährungsforschung
Volume 47, 2002 - Issue 2