Studies of Human Maximal and Minimal Safe Intake and Requirement of Selenium

Abstract

Although the geographical relationship between human cancer incidence and local environmental Se status has been repeatedly confirmed since 1969 (Shamberger and Frost 1969), the levels of Se used in animal studies, which support the role of Se as inhibiting cancer development, are potentially toxic. It was proposed that the justification for carrying out human intervention trials with Se to prevent cancer should be at best marginal or in the pharmacologic range. A promising approach to resolve the dose problem was the suggested use of levels similar to the intakes of populations residing in regions naturally high in Se (Clark and Combs 1986). Such an investigation has been launched since 1985 in a seleniferous area in Enshi (Yang et al. 1988 a, b). A daily Se intake of 50 μg by extrapolation from animals was proposed to meet the human requirement. Since extremely low Se areas with Se-deficiency-related endemic diseases appear in China, the study of the human requirement has been conducted since 1983, and part of the work was recently confirmed in non-affected areas (Yang et al. 1988 c). The results mentioned above are presented here.

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