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Vitamin E kinetics in smokers and nonsmokers
M G Traber1, B M Winklhofer-Roob, J M Roob
1Department of Internal Medicine, University of California, Davis, School of Medicine, Sacramento, CA, USA. maret.traber@orst.edu
Free Radical Biology & Medicine
|December 1, 2001
Summary
Cigarette smoking appears to increase the body's utilization of vitamin E, leading to a faster disappearance of plasma vitamin E in smokers compared to non-smokers. Further research is needed to confirm these findings and understand the underlying mechanisms.
Area of Science:
- Biochemistry
- Human Physiology
- Nutritional Science
Background:
- Vitamin E is a crucial fat-soluble antioxidant essential for cellular protection.
- Cigarette smoking is known to induce oxidative stress, potentially increasing the demand for antioxidants like vitamin E.
- The in vivo utilization and metabolism of vitamin E in smokers remain incompletely understood.
Purpose of the Study:
- To investigate whether cigarette smoking influences vitamin E utilization in the human body.
- To compare the plasma disappearance rates of natural and synthetic vitamin E in smokers versus non-smokers.
Main Methods:
- A controlled trial involving 6 smokers and 5 non-smokers of similar age and lipid profiles.
- Daily oral supplementation with both natural (d(3)-RRR) and synthetic (d(6)-all rac-alpha-tocopheryl acetates) vitamin E for 7 days.
- Regular blood sampling to measure plasma concentrations of both vitamin E forms over time, including a 21-day follow-up.
Main Results:
- Plasma concentrations of natural vitamin E (d(3)-alpha-tocopherol) were approximately double that of synthetic vitamin E (d(6)-alpha-tocopherol) in both groups.
- Initial plasma percentages of d(3)-alpha-tocopherol were similar between smokers and non-smokers at the start of supplementation.
- A trend indicated a faster exponential disappearance of plasma d(3)-alpha-tocopherol in smokers (half-life 55.6 h) compared to non-smokers (half-life 72.1 h).
- By day 21, the percentage of d(3)-alpha-tocopherol remaining in plasma was significantly lower in smokers (1.4%) than in non-smokers (2.2%).
Conclusions:
- The study suggests that cigarette smoking may increase the utilization or turnover of vitamin E in vivo.
- Smokers exhibited a trend towards faster plasma vitamin E disappearance, indicating potentially higher vitamin E requirements or altered metabolism.
- Further investigation is warranted to confirm these preliminary findings and elucidate the specific mechanisms by which smoking affects vitamin E metabolism.