γ-Tocopherol, the major form of vitamin E in the US diet, deserves more attention

University of California, the Department of Molecular and Cell Biology, Berkeley, USA.
American Journal of Clinical Nutrition (Impact Factor: 6.92). 01/2002; 74(6):714-22.
Source: PubMed

ABSTRACT gamma-tocopherol is the major form of vitamin E in many plant seeds and in the US diet, but has drawn little attention compared with alpha-tocopherol, the predominant form of vitamin E in tissues and the primary form in supplements. However, recent studies indicate that gamma-tocopherol may be important to human health and that it possesses unique features that distinguish it from alpha-tocopherol. gamma-Tocopherol appears to be a more effective trap for lipophilic electrophiles than is alpha-tocopherol. gamma-Tocopherol is well absorbed and accumulates to a significant degree in some human tissues; it is metabolized, however, largely to 2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman (gamma-CEHC), which is mainly excreted in the urine. gamma-CEHC, but not the corresponding metabolite derived from alpha-tocopherol, has natriuretic activity that may be of physiologic importance. Both gamma-tocopherol and gamma-CEHC, but not alpha-tocopherol, inhibit cyclooxygenase activity and, thus, possess antiinflammatory properties. Some human and animal studies indicate that plasma concentrations of gamma-tocopherol are inversely associated with the incidence of cardiovascular disease and prostate cancer. These distinguishing features of gamma-tocopherol and its metabolite suggest that gamma-tocopherol may contribute significantly to human health in ways not recognized previously. This possibility should be further evaluated, especially considering that high doses of alpha-tocopherol deplete plasma and tissue gamma-tocopherol, in contrast with supplementation with gamma-tocopherol, which increases both. We review current information on the bioavailability, metabolism, chemistry, and nonantioxidant activities of gamma-tocopherol and epidemiologic data concerning the relation between gamma-tocopherol and cardiovascular disease and cancer.

Download full-text


Available from: Stephan Christen, Jul 21, 2015
  • Source
    • "In vitro studies also found that the α- T as an antioxidant has superiority over other tocopherols. However, few other studies found that the γ-T is more effective anti-inflammatory and antinitrative than α-T in the prevention of cancer, neurodegenerative and cardiovascular diseases [44] [45] [46]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Vitamin E (Vit E) has enormous potential for cancer growth inhibition and cancer prevention. It has been studied widely for its antioxidant, anti-inflammatory and anti-cancerous activity. The aim of this review is to provide a summary of the research so far in regards to Vit E and its role in the prevention of human esophageal squamous cell cancer (ESCC), which is among the most malignant types of cancers. Its prevalence is high in China and poses a serious threat to the health of the residents. Therefore, finding new strategies to prevent and lessen the risk of ESCC and comprehensive understanding of carcinogenesis is essential. This review will provide the brief guidelines in understanding of Vit E in the prevention of ESCC. The data suggest that the combination of tocopherols like γ-tocopherol-rich mixture of tocopherols (γ-TmT) would be highly effective to use in the future for the prevention of cancers.
  • Source
    • "γ-tocopherol is unique in many aspects. Compared with α-, γ-tocopherol is a slightly less potent antioxidant, with regard to electron-donating propensity, but it is superior in detoxifying electrophiles such as R(Nitrogen)OS, partially because of its ability to form a stable nitro adduct, 5-Nγ-Tocopherol (Jiang et al., 2001). Generally, tartary buckwheat contains higher levels of tocopherols than common buckwheat (Ahmed et al., 2013). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Buckwheat (Fagopyrum spp.) is a "pseudo-cereal" of great interest in the production of healthy foods since its flour, derived from achenes, is enriched with bioactive compounds and, due to the absence of gluten, may be used in composition of celiac diets. Amongst buckwheat species, F. tataricum achenes possess a larger amount of the antioxidant flavenol rutin than the common buckwheat F. esculentum. Ongoing climate change may favor plant susceptibility to the attack by pathogenic, often mycotoxigenic, fungi with consequent increase of mycotoxins in previously unexploited feeds and foodstuffs. In particular, Aspergillus flavus, under suitable environmental conditions such as those currently occurring in Italy, may produce aflatoxin B1 (AFB1), the most carcinogenic compound of fungal origin which is classified by IARC as Category 1. In this study, the viable achenes of two buckwheat species, F. tataricum (var. Golden) and F. esculentum (var. Aelita) were inoculated with an AFB1-producing A. flavus NRRL 3357 to analyze their relative performances against fungal invasion and toxin contamination. Notably, we sought the existence of a correlation between the amount of tocols/flavonols in the achenes of buckwheat, infected and non-infected with A. flavus, and to analyze the ability of the pathogen to grow and produce toxin during achene infection. Results suggest that achenes of F. tataricum, the best producer of antioxidant compounds in this study, are less susceptible to A. flavus infection and consequently, but not proportionally, to mycotoxin contamination compared with F. esculentum. Moreover, rutin-derived quercetin appears to be more efficient in inhibiting aflatoxin biosynthesis than the parent compound.
    International Journal of Food Microbiology 07/2014; 189C:1-10. DOI:10.1016/j.ijfoodmicro.2014.07.029 · 3.16 Impact Factor
  • Source
    • "This literature is supported by prospective epidemiologic studies linking dietary intakes of vitamin E or combined tocopherols to slower rate of age-related cognitive decline [13] [14] [15] and lower risk of Alzheimer's disease (AD) [15] [16] [17] [18] [19]. It is actually g-tocopherol that constitutes much of the vitamin E content in the U.S. food supply [20]. The vast majority of studies do not show cognitive benefit from supplements of a-tocopherol [21] [22] [23] [24] [25] [26] [27]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Randomized trials of α-tocopherol supplements on cognitive decline are negative, whereas studies of dietary tocopherols have shown benefit. We investigated these inconsistencies by analyzing the relations of α- and γ-tocopherol brain concentrations to Alzheimer's disease (AD) neuropathology among 115 deceased participants of the prospective Rush Memory and Aging Project. Associations of amyloid load and neurofibrillary tangle severity with brain tocopherol concentrations were examined in separate adjusted linear regression models. γ-Tocopherol concentrations were associated with lower amyloid load (β = ‒2.10, P = .002) and lower neurofibrillary tangle severity (β = ‒1.16, P = .02). Concentrations of α-tocopherol were not associated with AD neuropathology, except as modified by γ-tocopherol: high α-tocopherol was associated with higher amyloid load when γ-tocopherol levels were low and with lower amyloid levels when γ-tocopherol levels were high (P for interaction = 0.03). Brain concentrations of γ- and α-tocopherols may be associated with AD neuropathology in interrelated, complex ways. Randomized trials should consider the contribution of γ-tocopherol.
    Alzheimer's & dementia: the journal of the Alzheimer's Association 02/2014; 11(1). DOI:10.1016/j.jalz.2013.12.015 · 17.47 Impact Factor
Show more