Optimization of Selenoprotein P in Chinese Subjects

Condition(s) targeted: Selenium Deficiency

Intervention: 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 (Dietary Supplement); placebo (Dietary Supplement)

Phase: N/A

Status: Active, not recruiting

Sponsored by: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Official(s) and/or principal investigator(s):
Raymond F Burk, M.D., Principal Investigator, Affiliation: Vanderbilt University
Yiming Xia, Ph.D., Study Director, Affiliation: Sichuan CDC, Chengdu

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

Official title: Optimization of Selenoprotein P in Chinese Subjects

Study design: Prevention, Randomized, Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Placebo Control, Parallel Assignment, Efficacy Study

Primary outcome: Plasma selenoprotein P levels at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks

Secondary outcome:

Total plasma selenium concentrations at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks

Plasma glutathione peroxidase activity at 0, 4, 8, 12, 16, 20, 24, 32, and 40 weeks

24hr urinary selenium excretion at 0, 20 and 40 weeks

Hair selenium levels at 0, 20 and 40 weeks

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.

Minimum age: 17 Years. Maximum age: N/A. Gender(s): Both.

Criteria:

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

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

Related 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.

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.

Starting date: March 2007
Ending date: October 2008
Last updated: March 20, 2008