Optimization of Selenoprotein P in Chinese Subjects

The purpose of this study is to determine the amount of selenium as selenomethionine that is required to optimize selenoprotein P in selenium-deficient Chinese subjects

Study Overview

• Status: Completed
• Conditions: Selenium Deficiency
• Intervention / Treatment: Dietary supplement: placebo; Dietary supplement: 20 µg selenium; Dietary supplement: 40 µg selenium; Dietary supplement: 60 µg selenium; Dietary supplement: 80 µg selenium; Dietary supplement: 100 µg selenium; Dietary supplement: 120 µg selenium

Detailed Description

Selenium is an essential nutrient. The Recommended Dietary Allowance (RDA) for selenium is considered to be the amount required to optimize plasma selenoproteins. There are two selenoproteins present in the plasma: selenoprotein P (Se-P) and glutathione peroxidase 3 (GPX-3). Although the amount of selenium required to optimize GPX-3 has been determined, the amount required to optimize Se-P in the plasma remains unknown. We aim to determine this amount by supplementing selenium deficient subjects with varying amounts of selenium as selenomethionine.

The study will take place in Mianning County, China, where selenium status is low. Approximately 150 people will be screened for eligibility to participate in this study. 98 subjects will be enrolled. Background information obtained from each participant will be: age, height, weight and smoking status.

Subjects will be randomized to a selenium supplement group. The selenium supplement will contain either 0, 20, 40, 60, 80, 100, or 120 µg of selenium as selenomethionine. A CDC worker will visit each participant daily to give them their selenium supplement. The CDC worker will watch them take their supplement and will ask if they have any unanticipated problems. Blood samples of 20 ml will be obtained at weeks 0, 4, 8, 12, 16, 20, 24, 32, and 40. Hair samples and 24-hr urine collections will be obtained at 0, 20 and 40 weeks. The total study duration is 40 weeks.

• Study Type: Interventional
• Enrollment (Actual): 98
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Sichuan
    • Chengdu, Sichuan, China
      • Sichuan Center for Disease Control and Prevention (Sichuan CDC)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 17 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• aged 17 years or older
• healthy
• resident of Mianning County for at least 1 year
• hematocrit (PCV) of 30 or greater

Exclusion Criteria:

• subject has taken selenium supplements within the year prior to study
• subject plans to relocate during study

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

7

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 1; 20 µg selenium as selenomethionine	Dietary supplement: 20 µg selenium; 20 µg selenium as selenomethionine
Experimental: 2; 40 µg selenium as selenomethionine	Dietary supplement: 40 µg selenium; 40 µg selenium as selenomethionine
Experimental: 3; 60 µg selenium as selenomethionine	Dietary supplement: 60 µg selenium; 60 µg selenium as selenomethionine
Experimental: 4; 80 µg selenium as selenomethionine	Dietary supplement: 80 µg selenium; 80 µg selenium as selenomethionine
Experimental: 5; 100 µg selenium as selenomethionine	Dietary supplement: 100 µg selenium; 100 µg selenium as selenomethionine
Experimental: 6; 120 µg selenium as selenomethionine	Dietary supplement: 120 µg selenium; 120 µg selenium as selenomethionine
Placebo Comparator: 7; placebo	Dietary supplement: placebo; placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Plasma selenoprotein P levels at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks	40 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Total plasma selenium concentrations at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks	40 weeks
Plasma glutathione peroxidase activity at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks	40 weeks
24hr urinary selenium excretion at 0, 20 and 40 weeks	40 weeks
Hair selenium levels at 0, 20 and 40 weeks	40 weeks

Collaborators and Investigators

• Sponsor: Vanderbilt University
• Collaborators: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Investigators: Study Director: Yiming Xia, Ph.D., Sichuan CDC, Chengdu

Publications and helpful links

General Publications

• Xia Y, Hill KE, Byrne DW, Xu J, Burk RF. Effectiveness of selenium supplements in a low-selenium area of China. Am J Clin Nutr. 2005 Apr;81(4):829-34. doi: 10.1093/ajcn/81.4.829.
• Casey CE, Guthrie BE, Friend GM, Robinson MF. Selenium in human tissues from New Zealand. Arch Environ Health. 1982 May-Jun;37(3):133-5. doi: 10.1080/00039896.1982.10667551.
• Xia Y, Hill KE, Li P, Xu J, Zhou D, Motley AK, Wang L, Byrne DW, Burk RF. 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. Am J Clin Nutr. 2010 Sep;92(3):525-31. doi: 10.3945/ajcn.2010.29642. Epub 2010 Jun 23.

Study record dates

Study Major Dates

• Study Start: March 1, 2007
• Primary Completion (Actual): December 1, 2007
• Study Completion (Actual): October 1, 2008

Study Registration Dates

• First Submitted: January 25, 2007
• First Submitted That Met QC Criteria: January 25, 2007
• First Posted (Estimate): January 30, 2007

Study Record Updates

• Last Update Posted (Estimate): March 7, 2012
• Last Update Submitted That Met QC Criteria: March 6, 2012
• Last Verified: March 1, 2012

More Information

Terms related to this study

• Keywords: Optimization; Selenoprotein P; Selenium supplements
• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Protective Agents; Trace Elements; Micronutrients; Antioxidants; Selenium
• Other Study ID Numbers: DK58763-opt; R01DK058763 (U.S. NIH Grant/Contract)