The Role of Selenium in Special Endemic Diseases and Cancer in China

Abstract

The essentiality of selenium in animals has been well documented both in experimental animals (Schwarz and Foltz, 1957) and livestocks (Muth et al., 1958) in 1950’s. However, the direct evidence of an etiological relationship between selenium and human disease had not been established till the preventive effect of selenium on Keshan disease (KD), an endemic cardiomyopathy, was shown in 1975 (Keshan Disease Research Group of the Chinese Academy of Medical Sciences,1979). Recently, some evidence has emerged that another endemic disease of osteoarthropathy in nature, the Kashin-Beck disease, is also related to selenium deficiency. The reasons for China being the place of more than one endemic human disease related to selenium deficincy are that: (a) farmers (80% of the total Chinese population) live on rather monotonous dietary patterns mainly composed of plant foods, i,e. grains and vegetables; (b) the major dietary components are produced locally, and (c) the population in rural areas are non-mobile. Therefore, the low selenium status of local soil readily transfers through the diet to the local inhabitants and thus affects human health. Blood and food analysis in these endemic areas revealed that the selenium level in blood and foods are much lower than the values reported from New Zealand and Finland (Table 1). On the other hand, in consistent with studies carried out in the western countries, the interest of studying the possible effects of selenium in human cancers is growing rapidly in China and some encouraging epidemiological data have been obtained (Yu et al.,1985). This paper is going to describe some recent advances in studies on the relationship between low selenium and Kashin-Beck disease and cancer in China.