Selenium absorption from fish is as good as that from plant-based foods, finds new research carried out in the Netherlands and the UK.
Studies have suggested a link between selenium deficiency and diseases as diverse as cancer, heart disease, arthritis and AIDS. Most people do not consume the recommended daily amount of the mineral, which is found in vegetables, nuts, wholegrains and also fish. However, it has been debated whether selenium from fish is as bioavailable to humans as that from other sources. Bioavailability of selenium is dependant on the form (or speciation) of selenium.
Part of the EU-funded research assessed the bioavailability of selenium from cooked and processed trout compared with the bioavailability of selenium from yeast. Two parallel studies were carried out in the Netherlands and the United Kingdom. In each country, six healthy men consumed biosynthetically labelled cooked trout, six men consumed biosynthetically labelled raw salted trout and a further six men consumed biosynthetically labelled brewers' yeast. Absorption was measured using a faecal monitoring technique.
The studies showed that fish is a good source of selenium and bioavailability is not affected by processing (cooking or salt treatment). The mean absorption of selenium from fish was 85-90 per cent, compared with 50 per cent from yeast.
Another study was carried out as part of the project to evaluate if specific plasma selenoproteins could be used as markers of selenium status or selenium bioavailability in short-term meal studies. Nearly all of the selenium present in animals, plants and micro-organisms is associated with proteins. In human plasma, two selenoproteins have been identified: extracellular glutathione peroxidase and selenoprotein P.
In the meal studies carried out, no significant changes in extracellular glutathione peroxidase were observed, indicating that selenoprotein P is the preferred biochemical marker for these studies.
For more information on the project (FAIR-CT95-0771), contact Dr Joop Luten at the DLO-Netherlands Institute for Fisheries Research (RIVO).