An estimation of selenium requirements for New Zealanders

• Published in: The American journal of clinical nutrition Vol. 70; no. 5; pp. 896 - 903
• Main Authors: DUFFIELD, A. J, THOMSON, C. D, HILL, K. E, WILLIAMS, S
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Clinical Nutrition 01.11.1999; American Society for Clinical Nutrition, Inc
• Subjects: Adult; Biological and medical sciences; Dietary supplements; Double-Blind Method; Female; Glutathione Peroxidase - blood; Human physiology applied to population studies and life conditions. Human ecophysiology; Humans; Male; Medical sciences; Middle Aged; New Zealand; Nutrition; Nutrition Policy; Nutritional Requirements; Nutritional survey. Food supply and nutritional requirement; Proteins - metabolism; Radioimmunoassay; Selenium - administration & dosage; Selenium - blood; Selenoprotein P; Selenoproteins; Thyroxine - blood; New Zealand; Oceania; Glutathione peroxidase; Human; Enzyme; Supplemented diet; Antioxidant; Inorganic element; Feeding; Nutrient requirement; Dietary allowance; Selenoprotein; Peroxidases; Enzymatic activity; Thyroxine; Thyroid hormone; Oxidoreductases; Selenium
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/70.5.896

Current US dietary recommendations for selenium are based on maximization of plasma glutathione peroxidase (GSHPx) activity according to data from one study of Chinese men. The effect of various amounts of supplemental selenium on GSHPx activities in blood of New Zealand adults was investigated to calculate a selenium requirement for New Zealanders. The effect on plasma selenoprotein P and thyroid hormones was also investigated. Fifty-two adults with low blood selenium concentrations ingested a placebo or 10, 20, 30, or 40 microgram Se as L-selenomethionine daily for 20 wk. Plasma and whole-blood GSHPx activities increased in all supplemented groups but reached a plateau only in the group receiving 40 microgram Se, as determined by statistical analysis. Increases in selenoprotein P were greater than those for selenium and GSHPx at all supplement intakes. Thyroxine concentrations decreased in supplemented groups but the decrease was significantly different from that in the control group only for the 10-microgram group and for all supplemented groups combined. An upper estimated requirement of 90 microgram Se/d was calculated as the intake necessary for maximization of plasma GSHPx activity, as used in the derivation of the US recommended daily allowance. Our lower estimated requirement of 39 microgram Se/d was the intake necessary to reach two-thirds of maximal GSHPx activity, as was used in calculating the World Health Organization normative requirement. The lower estimate is a realistic goal for New Zealand but the upper estimate could be achieved only with regular inclusion of high-selenium foods.