Selenium in foods - geological, geographical, agricultural and Socio-economic factors.
The concentration of Selenium in Foods depends on a number of geological, geographical, agricultural and Socio-economic factors.
Diplock, 1993; Fordyce et al. 2000; Johnson et al. 2000; Adams et al. 2002.
Briefly, Soils in different parts of the world have varying concentrations and bioavailable Selenium.
Parts of China, New Zealand, Europe and Africa have insufficient soil Selenium. Parts of America have excess Selenium.
In Keshan Province in North East China there is almost no soil selenium, and indemic cardiomyopathy (Keshans’ Disease) caused many deaths until it was realised that supplemental Selenium prevented the heart disease.
(Riley 1996.) Likewise for degenerative Cartilage condition called Kashin-becks disease.
In more recent years pollution has caused a major reduction of bioavailable soil Selenium. The advent of increased Acid rain, air pollutants - increased fossil fuel useage, Sulphur, phosphates, heavy metals i.e. mercury, have leached, combined with available soil selenium, so effectively reducing its bioavailabilty to the plants and hence to our diets.
Large scale monoagricultural practices combined with extensive fertilisation have also contributed to reduction of selenium in the soils.
Geopolitical factors such as where food is grown play a significant part in the food supply. For example the production of wheat in areas deficient of Selenium affect the diets of its users e.g This was seen in New Zealand because of their selenium deficient soils reverted to the importation of large quantities of Australian wheat in preference to consuming their own over the last decade, so as to increase their populations average Selenium levels.
The trade dispute between the European Common market and the U.S.A has affected the importation of wheat grown in selenium rich soils. This has lead to a lowering of serum selenium levels on the continent and a corresponding increase in various cancers and other conditions associated with Selenium deficiency.





