Oxidative Stress and Vitamin E Requirements

Oxidative Stress and Vitamin E Requirements

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.

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.

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