Selenium in food and nutrition in Finland. An overview on research and action.

For geochemical reasons Finland is a low-selenium area. In the 1960's several diseases associated with serious Se deficiency were observed in domestic animals. Selenium medication of animals and selenium supplementation of animal feeds from 1969 effectively eliminated these diseases. An extensive study of the trace element content of foods consumed in Finland in the 1970's demonstrated that the dietary intake of selenium was exceptionally low (25 micrograms/day/10 MJ) during the years when domestic grains were used. A study carried out in 1981 showed that supplementation of healthy middle-aged men with high selenium wheat or yeast or selenate double the glutathione peroxidase activity in platelets. Prospective epidemiological studies based on cohorts that were followed in the 1970's suggested that low selenium (less than 45 ng/ml serum) might be a risk factor for cardiovascular diseases and cancer. Technologies to increase the selenium content of foods and feeds were developed and an official decision was reached to add, starting in 1984, sodium selenate to the main fertilizers to increase the selenium content of domestic grain to about 100 micrograms/kg. This measure will increase the average selenium intake above 50 micrograms/d even in the years when grain with a high selenium content is not imported.