Plasma RRR-α-tocopherol Concentrations Are Lower in Smokers Than in Non-Smokers after Ingestion of a Similar Oral Load of this Antioxidant Vitamin

Abstract

1. Using deuterium-labelled alpha-tocopherol (vitamin E), the plasma kinetics of alpha-tocopherol derived from supplemental RRR-alpha-tocopherol and RRR-alpha-tocopheryl acetate were determined in asymptomatic individuals who smoke and, for comparison, in a group of healthy non-smokers. 2. Venous blood samples were withdrawn 6, 12 and 27 h after the oral administration of a gelatin capsule containing an equimolar mixture of RRR-alpha-tocopheraol and RRR-alpha-tocopheryl acetate. Plasma concentrations of endogenous and administered forms of alpha-tocopherol were determined by a combination of HPLC and GC-MS. 3. Both the free phenol and the acetate ester concentrations of alpha-tocopherol were lower in smokers than in non-smokers: 0.99 versus 1.60 (P < 0.05) and 0.66 versus 1.49 (P < 0.05) mumol/mmol cholesterol for RRR-alpha-tocopherol and RRR-alpha-tocopheryl acetate respectively. The highest concentation of alpha-tocopherol derived from administered RRR-alpha-tocopherol and its acetate ester were observed in plasma at 12 h (compared with 6-h and 27-h measurements) in most subjects. 4. Although the two forms of alpha-tocopherol were administered in equal doses, plasma from smokers contained significantly higher concentrations of RRR-alpha-tocopherol derived from the free phenol form than from the acetate form (0.99 versus 0.66 mumol/mmol cholesterol, P < 0.05, 12 h). Non-smokers did not exhibit preferential uptake of either form of vitamin E. 5. These results suggest that individuals who smoke have either a reduced ability to absorb alpha-tocopherol, particularly when it is presented as the acetate ester, or increased clearance of newly absorbed alpha-tocopherol compared with non-smokers.

Vitamin E bioavailability in humans

“…Previous studies have consistently shown lower levels of certain plasma antioxidants in smokers (Dietrich et al, 2003) and increased levels of oxidative products such as F 2 -isoprostanes (Morrow et al, 1995). However, the effects of smoking on vitamin E status is less clear, with some studies having observed comparable circulating levels (Lykkesfeldt et al, 2000) while others reporting decreased concentrations in smokers relative a non-smoking groups (Munro et al, 1997). We have shown recently that smokers have decreased a-tocopherol levels in lymphocytes and platelets even though plasma levels were similar to non-smokers (Jeanes et al, 2004b).…”

Effect of Young Barley Leaf Extract and Adlay on Plasma Lipids and LDL Oxidation in Hyperlipidemic Smokers

“…This is consistent with the observation that smokers have lower antioxidative capacity, likely due to reduced circulating antioxidants (such as a-tocopherol and ascorbic acid) and increased free radical levels than nonsmokers. 4,5) Therefore, the supplement of antioxidants was not as effective in smokers as in nonsmokers. Although the antioxidative effect of adlay was not as strong as that of BL, the current finding that adlay showed an antioxidative effect was unexpected.…”

“…4) Ascorbic acid and possibly tocopherols have a high turnover in smokers, which can promote the development of the atheromatous plaque. 5) Young barley leaf extract (BL) is a good natural source of vitamins and minerals. It is made from barley leaves harvested 2 weeks after seeding.…”

Effects of Smoking and Need for Cessation: Biochemical and Pharmacological Feedback

“…Reactive oxygen species are generated through various metabolic processes and destroyed by antioxidants, including vitamins A, C, and E, otherwise they are likely contributing to the development of cancer, heart disease, and cataracts [30]. Oxidants also speed up blood vessel damage due to atherosclerosis [31].…”