Upper Tolerable Nutrient Level for Selenium

Reference from the joint report of FAO/WHO expert consultation on Human Vitamins and Minerals verbatim.

80. WHO. 1987. Selenium, Geneva, World Health Organization. (Environmental Health Criteria, 58).

A comprehensive account of the clinically significant biochemical manifestations of chronic and acute intoxication from selenium arising from high concentrations in food, drinking water, and the environment were published jointly by WHO and the United Nations Environment Programme and the International Labour Organisation (80).

44. Levander, O.A. 1987. A global view of human selenium nutrition. Annu. Rev. Nutr., 7:

227-250. 

93. Smith, M.I., Franke, K.W. & Westfall, B.B. 1936. The selenium problem in relation to publish health. US Public Health Report., 51: 1496-1505.

94. Smith, M.I. & Westfall, B.B. 1937. Further field studies on the selenium problem in

relation to public health. US Public Health Report, 52: 1375-1384.

This report (44) stresses that the signs and symptoms of human overexposure to selenium are not well defined. Common clinical features are hair loss and structural changes in the keratin of hair and of nails, the development of icteroid skin, and gastrointestinal disturbances (93, 94).

95. Yang, G., Wang, S., Zhou, R. & Sun, S. 1983. Endemic selenium intoxication of Humans in China. Am. J. Clin. Nutr., 37: 872-881.

96. Hadjimarkos, D.M. 1973. Selenium in relation to dental caries. Food Cosmetic Toxicol., 11: 1083-1095.

97. Hadjimarkos, D.M., Storveik, C.A. & Renmert, L.T. 1952. Selenium and dental casies. An investigation among school children of Oregon. J. Paediatr., 40: 451-455.

An increased incidence of nail dystrophy has been associated with consumption of high-selenium foods supplying more than 900 μg/day. These foods were grown in selenium-rich (seleniferous) soil from specific areas in China (95). A positive association between dental caries and urinary selenium output under similar circumstances was reported (96, 97).

98. National Research Council. 1980. Mineral Tolerance of Domestic Animals. Commission on Natural Resources., Washinton, D.C. National Academy of Sciences.

Sensitive biochemical markers of impending selenium intoxication have yet to be developed. In their absence it is suggested that the upper tolerable nutrient intake level (UL) for selenium should be set, provisionally, at 400 μg/day for adults. It is noteworthy that a maximum tolerable dietary concentration of 2 mg/kg dry diet was suggested for all classes of domesticated livestock and has proved satisfactory in use (98). This suggests that the proposed UL of 400 μg/day for human subjects provides a fully adequate margin of safety. The UL for children and for pregnant or lactating women has yet to be determined.