Selenium Low in British Diets
~ October 1997 No.18 ~
In a recent editorial of the British Medical Journal a researcher at the University of Surrey raised concern about the selenium status of the British population. Dr. Margaret Rayman pointed out that over the past 22 years the intake of selenium in Britain has declined from 60 ug / day to 34 ug / day. The selenium values reported in a survey of British foods carried out by the British Ministry of Agriculture, Fisheries and Foods indicate that most Britons may not be eating large enough quantities of selenium to meet the British governments own reference nutrient intakes for selenium - 75 ug / day for men and 60 ug /day for women. In North America the recommended daily allowance (RDA) is 70 ug/day for adult men and 55 ug/day for adult women.
Selenium is an essential element. It must be part of the diet. The body can’t make it. Selenium is part of many key enzymes that participate in a diversity of metabolic functions. For example selenoenzymes are involved in antioxidant reactions and thyroid hormone metabolism. In addition proteins that contain selenium can be found in male gonads and the sperm tails.
Normally selenium is taken up by plants from the soil. The quantity of selenium in the soil, the use of fertilizers and such things as acid rain can all affect the amount of selenium that ends up in the plant. In certain regions of China, were the selenium content of the soil is extremely low, deficiency diseases have been reported.
For most North American and European consumers wheat flour is the major source of selenium in the diet. Dr. Rayman speculated that the drop in the selenium status of Britons could be the result of a switch away from North American wheat in favour of less selenium rich European wheats and changes in bread making technologies.
Dr. Rayman pointed out that farm animals routinely get mineral supplements containing selenium and that in Finland sodium selenate has been added to fertilizers for over a decade. In light of recent reports about the link between selenium intake and the risk of cancer, there is even more reason to be concerned about low dietary intakes of selenium.
|Food||Se content (micrograms/100 g food)|
|Metabolism :||selenium has important antioxidant properties because it is an essential component of the enzyme glutathione peroxidase. This enzyme maintains low levels of hydrogen peroxides and organic peroxides in the cell.|
Dietary selenium: time to act