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gamma-Tocopherol biokinetics and transformation in humans
Francesco Galli1, Rosalind Lee, Jeffrey Atkinson
1Lung Biology, School of Health and Life Sciences, King's College, London, UK. f.galli@unipg.it
Free Radical Research
|January 6, 2004
Summary
Supplementing with gamma-tocopherol (gamma-T) acetate transiently boosts plasma gamma-T levels and its metabolite, gamma-CEHC, in healthy adults. These changes are temporary, with levels returning to baseline within 72 hours.
Area of Science:
- Nutritional Science
- Human Metabolism
- Pharmacokinetics
Background:
- Human uptake and biotransformation of gamma-tocopherol (gamma-T) remain poorly understood.
- Investigating gamma-T metabolism is crucial for understanding its biological role and potential supplementation benefits.
Purpose of the Study:
- To investigate the uptake and biotransformation of gamma-tocopherol (gamma-T) in humans.
- To assess the response to gamma-T supplementation using a stable isotope method.
Main Methods:
- Administered deuterium-labeled gamma-T acetate (d(2)-gamma-TAC) to 21 healthy subjects with a meal.
- Collected blood and urine samples over 240 hours post-supplementation.
- Measured concentrations of d(2) and d(0)-gamma-T and its metabolite gamma-CEHC using GC-MS.
Main Results:
- Plasma gamma-T and gamma-CEHC concentrations increased significantly (6-14 fold) post-supplementation, with marked inter-individual variability.
- All measured parameters returned to baseline levels within 72 hours.
- Gamma-T supplementation minimally affected alpha-tocopherol (alpha-T) concentrations and metabolism.
Conclusions:
- Ingestion of gamma-T acetate transiently increases plasma gamma-T and its metabolite gamma-CEHC.
- The metabolism of gamma-T appears tightly regulated, maintaining distinct alpha-T to gamma-T and gamma-CEHC to alpha-CEHC ratios.
- Gamma-T supplementation does not significantly alter the existing plasma alpha-T pool or its metabolism.