RESEARCH The vitamin E isoforms α-t i h

Full list of author information is available at the end of the articleBackground There are seemingly conflicting results in clinical stud-ies with vitamin E. As we discuss in a recent perspec-tive [1] and recent reviews [2-4], conflicting outcomes in clinical studies and differences in prevalence of aller-gic disease among countries may, at least in part, reflect differences in the serum levels of γ-tocopherol. There are four tocopherol isoforms of vitamin E: α-tocopherol, γ-tocopherol, β-tocopherol and δ-tocopherol. The vitamin E isoforms, α-tocopherol and γ-tocopherol are the most abundant in diet and tissues, and α-tocopherol is the most studied. α-tocopherol and γ-tocopherol differ by one me-thyl group and, at equal molar concentrations, have a rela-tively similar capacity to scavenge reactive oxygen species (ROS) [5,6]. In contrast to α-tocopherol, γ-tocopherol also reacts with reactive nitrogen species [7] and may be bene-ficial for inflammation with increases in reactive nitroge