Clinical trial NCT00067899: Oxidative Stress and Vitamin E Requirements
Official title: Oxidative Stress and Vitamin E Requirements
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE2
Conditions: Smoking
Keywords: cigarette smoking
tocopherol
bioavailability
metabolism
oxidative stress
Lead sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Sponsor class: NIH
First posted: 2003-09-08
Enrollment: 99
Sex: ALL
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: The purpose of this study is to determine if oxidative stress derived from cigarette smoking increases vitamin E requirements. The study will also assess the role of vitamin C in modulating vitamin E requirements. Vitamin E requirements will be assessed by measuring vitamin E in plasma as well as by measuring the excreted vitamin E metabolite in the urine.

Detailed description: We will be investigating the fractional disappearance rate of tocopherols in cigarette smokers compared to nonsmokers. This will be accomplished by supplementing individuals with deuterium labeled alpha- and gamma-tocopherols. Quantification of plasma tocopherols as well as urinary metabolites, alpha- and gamma-carboxy ethyl hydroxychromanol, will be determined using liquid chromatography/mass spectrometry analysis. In addition, the role of vitamin C as it pertains to its influence on the fraction disappearance rate of vitamin E will also be evaluated.

Eligibility criteria: Inclusion criteria:

* non-smoking status or smokers (more than 1 pack per day)
* age: 18-35 y
* stable body weight, ranging between 80% and 130%,
* maintenance of normal exercise and activity patterns
* total cholesterol ≤ 7.758 mmol/L (300 mg/dl)
* triglyceride concentration ≤ 3.387 mmol/L (300 mg/dl)

Subjects will be excluded if they fulfill any one of the following:

* antioxidant supplement users
* resting blood pressure above 160/105 mm Hg
* engaged in aerobic activity more than five hours per week
* vegetarian or other restrictive dietary requirements
* fasting blood glucose concentration of ≥ 7.77 mmol/L (140 mg/dl)
* history of diabetes or uremia
* other known metabolic disease or medication use known to affect lipid metabolism

Primary outcomes:
Secondary outcomes:
Other outcomes:
Locations:
city: Corvallis
country: United States
facility: Linus Pauling Institute - Oregon State University
state: Oregon
Study officials:
References:
citation: Traber MG, Winklhofer-Roob BM, Roob JM, Khoschsorur G, Aigner R, Cross C, Ramakrishnan R, Brigelius-Flohe R. Vitamin E kinetics in smokers and nonsmokers. Free Radic Biol Med. 2001 Dec 1;31(11):1368-74. doi: 10.1016/s0891-5849(01)00723-7.
citation: Dietrich M, Block G, Norkus EP, Hudes M, Traber MG, Cross CE, Packer L. Smoking and exposure to environmental tobacco smoke decrease some plasma antioxidants and increase gamma-tocopherol in vivo after adjustment for dietary antioxidant intakes. Am J Clin Nutr. 2003 Jan;77(1):160-6. doi: 10.1093/ajcn/77.1.160.
citation: Traber MG, van der Vliet A, Reznick AZ, Cross CE. Tobacco-related diseases. Is there a role for antioxidant micronutrient supplementation? Clin Chest Med. 2000 Mar;21(1):173-87, x. doi: 10.1016/s0272-5231(05)70016-2.