Cigarette Smokers have Decreased Lymphocyte and Platelet α-tocopherol Levels and Increased Excretion of the γ-tocopherol Metabolite γ-carboxyethyl-hydroxychroman (γ-CEHC)

Abstract

Cigarette smoking is associated with increased oxidative stress and increased risk of degenerative disease. As the major lipophilic antioxidant, requirements for vitamin E may be higher in smokers due to increased utilisation. In this observational study we have compared vitamin E status in smokers and non-smokers using a holistic approach by measuring plasma, erythrocyte, lymphocyte and platelet α- and γ-tocopherol, as well as the specific urinary vitamin E metabolites α- and γ-carboxyethyl-hydroxychroman (CEHC). Fifteen smokers (average age 27 years, smoking time 7.5 years) and non-smokers of comparable age, gender and body mass index (BMI) were recruited. Subjects completed a 7-day food diary and on the final day they provided a 24 h urine collection and a 20 ml blood sample for measurement of urinary vitamin E metabolites and total vitamin E in blood components, respectively. No significant differences were found between plasma and erythrocyte α- and γ-tocopherol in smokers and non-smokers. However, smokers had significantly lower α-tocopherol (mean±SD, 1.34±0.31 μmol/g protein compared with 1.94±0.54, P=0.001) and γ-tocopherol (0.19±0.04 μmol/g protein compared with 0.26±0.08, P=0.026) levels in their lymphocytes, as well as significantly lower α-tocopherol levels in platelets (1.09±0.49 μmol/g protein compared with 1.60±0.55, P=0.014; γ-tocopherol levels were similar). Interestingly smokers also had significantly higher excretion of the urinary γ-tocopherol metabolite, γ-CEHC (0.49±0.25 mg/g creatinine compared with 0.32±0.16, P=0.036) compared to non-smokers, while their α-CEHC (metabolite of α-tocopherol) levels were similar. There was no significant difference between plasma ascorbate, urate and F₂-isoprostane levels.

Therefore in this population of cigarette smokers (mean age 27 years, mean smoking duration 7.5 years), alterations to vitamin E status can be observed even without the more characteristic changes to ascorbate and F₂-isoprostanes. We suggest that the measurement of lymphocyte and platelet vitamin E may represent a valuable biomarker of vitamin E status in relation to oxidative stress conditions.

• Vitamin E
• Oxidative stress
• Metabolites
• Lymphocytes
• Platelets