Optimization of selenoprotein P and other plasma selenium biomarkers for the assessment of the selenium nutritional requirement: a placebo-controlled, double-blind study of selenomethionine supplementation in selenium-deficient Chinese subjects

• Published in: The American journal of clinical nutrition Vol. 92; no. 3; pp. 525 - 531
• Main Authors: Xia, Yiming, Hill, Kristina E, Li, Ping, Xu, Jiayuan, Zhou, Dingyou, Motley, Amy K, Wang, Li, Byrne, Daniel W, Burk, Raymond F
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Nutrition 01.09.2010; American Society for Clinical Nutrition, Inc
• Subjects: Adult; adults; Asian People; Biomarkers; Biomarkers - blood; blood chemistry; Diet; dietary mineral supplements; dietary minerals; dosage; Double-Blind Method; enzyme activity; glutathione peroxidase; Glutathione Peroxidase - blood; Humans; methionine; nutrient intake; nutrient requirements; Nutrition; Nutritional Requirements; nutritional status; Plasma; protein synthesis; Proteins; Selenium; Selenium - blood; Selenium - deficiency; selenomethionine; Selenomethionine - pharmacology; selenoprotein P; Selenoprotein P - blood; temporal variation; China
• ISSN: 0002-9165; 1938-3207
• DOI: 10.3945/ajcn.2010.29642

BACKGROUND: The intake of selenium needed for optimal health has not been established. Selenoproteins perform the functions of selenium, and the selenium intake needed for their full expression is not known. OBJECTIVE: This study sought to determine the intake of selenium required to optimize plasma selenoprotein P (SEPP1) and to compare SEPP1 with other plasma selenium biomarkers. DESIGN: A 40-wk placebo-controlled, double-blind study of selenium repletion was carried out in 98 healthy Chinese subjects who had a daily dietary selenium intake of 14 mu g. Fourteen subjects each were assigned randomly to daily dose groups of 0, 21, 35, 55, 79, 102, and 125 mu g Se as L-selenomethionine. Plasma glutathione peroxidase (GPX) activity, SEPP1, and selenium were measured. A biomarker was considered to be optimized when its value was not different from the mean value of the subjects receiving larger supplements. RESULTS: The SEPP1 concentration was optimized at 40 wk by the 35- mu g supplement, which indicated that 49 mu g/d could optimize it. GPX activity was optimized by 21 mu g (total ingestion: 35 mu g/d). The selenium concentration showed no tendency to become optimized. CONCLUSIONS: The present results indicate that SEPP1 concentration is the best plasma biomarker studied for assessing optimal expression of all selenoproteins, because its optimization required a larger intake of selenium than did GPX activity. On the basis of the selenium intake needed for SEPP1 optimization with adjustments for body weight and individual variation, ap 75 mu g Se/d as selenomethionine is postulated to allow full expression of selenoproteins in US residents. This trial was registered at clinicaltrials.gov as NCT00428649.