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United States Department of Agriculture

Agricultural Research Service

Research Project: DIETARY MODULATION OF OBESITY-RELATED CANCER BY SELENIUM

Location: Dietary Prevention of Obesity-related Disease Research

Title: Differential responses to selenomethioinine supplementation by sex and genotype in healthy adults)

Author
item Combs, Gerald
item Jackson, Matthew
item Watts, Jennifer
item Johnson, Luann
item Zeng, Huawei
item Idso, Joseph
item Schomburg, Lutz
item Hoeg, Antonia
item Hoefig, Carolin
item Chiang, Emily
item Waters, David
item Tsuji, Petra
item Davis, Cindy
item Milner, John

Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2011
Publication Date: 5/12/2012
Publication URL: http://handle.nal.usda.gov/10113/58166
Citation: Combs, G.F., Jackson, M.I., Watts, J.J., Johnson, L.K., Zeng, H., Idso, J.P., Schomburg, L., Hoeg, A., Hoefig, C.S., Chiang, E.C., Waters, D.J., Tsuji, P.A., Davis, C.D., Milner, J.A. 2012. Differential responses to selenomethioinine supplementation by sex and genotype in healthy adults. British Journal of Nutrition. 107:1514-1525.

Interpretive Summary: Because selenium (Se) supplementation has been shown to reduce cancer risk in subjects with initial plasma Se concentrations <106 ng/ml, it would be useful to know the Se intake required to achieve such a threshold. We conducted a randomized, double-blind, intervention trial to determine the responses of multiple biomarkers of Se status in 216 healthy adults during a year-long intervention with selenomethionine (SeMet). We measured the responses of several biomarkers of Se status relative to genotype of four selenoproteins, dietary Se intake and parameters of single-carbon metabolism. We found supplemental SeMet not to affect plasma activities of two Se-dependent proteins, glutathione peroxidase and selenoprotein P, but produced significant, dose-dependent increases in the Se contents of plasma, urine and buccal cells that plateaued by 9-12 mos and were linearly related to effective Se dose (µg/day/kg0.75). The increase in urinary Se excretion was greater for women than men, and for individuals of the GPX1 679 T/T genotype than for those of the GPX1 679 C/C genotype. Our results show that, for non-deficient adults, the Se intake (as SeMet) required to support plasma Se concentration at a target level (Sepl-target) is: Sein = (Sepl-target - Sepl)/18.2 ng d kg0.75 ml-1ug-1.

Technical Abstract: Background: Selenium (Se) supplementation may reduce cancer risk in subjects with initial plasma Se concentrations <106 ng/ml. It would be useful to know the Se intake required to achieve such a threshold. Objective: Characterize the responses of multiple biomarkers of Se status in healthy adults during a year-long intervention with selenomethionine (SeMet). Design: A total of 261 men and women were randomized to four doses of Se (0, 50, 100 or 200 µg/day as L-SeMet) for 12 months. Responses of several biomarkers of Se status (plasma Se, plasma seleoprotein P [SEPP1], plasma glutathione peroxidase activity [GPX3], buccal cell Se, urinary Se) were determined relative to genotype of four selenoproteins (GPX1, GPX3, SEPP1, selenoprotein 15 [SEP15]), dietary Se intake and parameters of single-carbon metabolism. Results: Supplemental SeMet did not affect GPX3 activity or SEPP1 concentration, but produced significant, dose-dependent increases in the Se contents of plasma, urine and buccal cells that plateaued by 9-12 mos and were linearly related to effective Se dose (µg/day/kg0.75). The increase in urinary Se excretion was greater for women than men, and for individuals of the GPX1 679 T/T genotype than for those of the GPX1 679 C/C genotype. Conclusions: The most responsive biomarkers of Se status were those related to body Se pools: plasma, buccal cell, urinary Se concentrations. The change in plasma Se resulted from increases in its non-specific component. For non-deficient adults, the Se intake (as SeMet) required to support plasma Se concentration at a target level (Sepl-target) is: Sein= (Sepl-target – Sepl)/18.2 ng d kg0.75 ml-1ug-1.

Last Modified: 8/24/2016
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