Effect of vitamin E on exhaled ethane in cigarette smokers

Chest. 1999 Mar;115(3):684-90. doi: 10.1378/chest.115.3.684.


Study objectives: We hypothesized that micronutrient antioxidant intake may be one factor determining the development of significant COPD. Vitamin E was administered to smokers to determine if exhaled ethane was reduced and if ethane correlated with measures of lung function.

Study design: Longitudinal placebo lead-in trial with posttreatment observation period.

Setting: Tucson Veterans Affairs Medical Center.

Participants: Twenty-nine current stable smokers having no interest in smoking cessation.

Interventions: Spirometry, exhaled breath ethane measurements, and vitamin E and [-carotene plasma levels followed by 3 weeks of placebo with repeat plasma vitamin levels and ethane measurements; next, 3 weeks of vitamin E (dl-a-tocopherol), 400 IU po bid followed by plasma vitamin levels and breath ethane measurements; finally, 3 weeks without vitamins followed by breath ethane and plasma vitamin levels.

Results: Vitamin E treatment did not reduce ethane significantly. Exhaled ethane levels (mean + SD: pm/min/kg) were as follows: baseline, 7.39 + 5.39; after run-in period, 6.86 + 4.09; after vitamin E, 6.36+/-3.02; and final, 7.23+/-4.63. After vitamin E therapy, a significant negative correlation existed between exhaled ethane and FEV1/FVC. Pack-years of smoking at baseline and after vitamin E were significantly associated with ethane exhaled. Initial lung function was not significantly negatively associated with vitamin E-induced changes in exhaled ethane but a negative trend was found.

Conclusions: Vitamin E alone, unlike the combination of vitamins C, E, and beta-carotene, failed to reduced exhaled ethane in cigarette smokers. Exhaled ethane was correlated with pack-years of smoking. Smokers whose ethane values were found to fall the most tended to have better preserved lung function.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Aged
  • Breath Tests
  • Ethane / metabolism*
  • Female
  • Forced Expiratory Volume
  • Humans
  • Lipid Peroxidation
  • Male
  • Middle Aged
  • Respiratory Function Tests
  • Smoking / metabolism*
  • Vital Capacity
  • Vitamin E / pharmacology*


  • Vitamin E
  • Ethane