α-Tocopherol supplementation reduces 5-nitro-γ-tocopherol accumulation by decreasing γ-tocopherol in young adult smokers.
Level 3 - non-randomized controlled study
Non-randomized controlled interventional study comparing smokers and non-smokers
PubMed 25966030 · doi:10.3109/10715762.2015.1040788
What was done
Eleven healthy smokers (age 21 ± 1 y) and ten non-smokers (age 21 ± 2 y) ingested 75 mg/d each of RRR- and all-rac-α-tocopheryl acetate for 6 consecutive days. Plasma concentrations of α-tocopherol (α-T), γ-tocopherol (γ-T), γ-carboxyethyl hydroxychromanol (γ-CEHC), 5-nitro-γ-tocopherol (NGT), and nitrate/nitrite were measured at baseline (Pre), the morning after 6 days of supplementation (Post 1), and on days 6 (Post 6) and 14 (Post 14) post-supplementation.
What was found
Supplementation increased plasma α-T and decreased γ-T in both groups, returning to baseline by Post 6. Plasma γ-CEHC increased after the first dose in both cohorts. Baseline plasma NGT and nitrate/nitrite were higher in smokers than non-smokers. In smokers, plasma NGT was reduced on Post 1 and Post 6 and returned to baseline on Post 14. Plasma nitrate/nitrite showed a trend toward increasing post-supplementation only in smokers (P = 0.07). Plasma NGT correlated with γ-T more strongly in smokers (R = 0.83, P < 0.05) than non-smokers (R = 0.50). Absolute plasma concentration values were not reported in the abstract.
Why it matters
Supplementing with α-tocopherol lowers circulating γ-tocopherol, which may impair the clearance of reactive nitrogen species in individuals under elevated nitrative stress, such as smokers.
Limits
The study had a very small sample size (n = 21) and was non-randomized with no placebo control arm. The intervention lasted only 6 days, limiting conclusions about long-term supplementation effects.
Cited by
- supports High doses of alpha-tocopherol lower circulating levels of gamma-tocopherol in the body.