China
Africa
Explore chapters and articles related to this topic
Free Radicals and Antioxidants
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Due to its high antioxidant activity, vitamin E has been proposed for prevention against colon, prostate and breast cancers, some cardiovascular diseases, ischemia, cataract, arthritis and certain neurological disorders (6, 119–120). However, a recent meta-analysis suggests that alpha-tocopherol supplements may actually increase all-cause mortality; however, the mechanism for this increased risk is unknown (120).
Tocopherol
Published in Anton C. de Groot, Monographs in Contact Allergy, 2021
Vitamin E is found in many dietary products. Pharmaceutical tocopherol can be used as a dietary supplement for patients with a deficit of vitamin E. Vitamin E deficiency is rare, and it is primarily found in premature babies of very low birth weight, patients with fat malabsorption and patients with α-β-lipoproteinemia, which is a rare, inherited disorder that causes poor absorption of dietary fat.
Role of Vitamin D and Antioxidants in the Prevention and Treatment of Alzheimer’s Disease
Published in Abhai Kumar, Debasis Bagchi, Antioxidants and Functional Foods for Neurodegenerative Disorders, 2021
Shilia Jacob Kurian, Ruby Benson, Sonal Sekhar Miraj, Mahadev Rao
Vitamin E is recognized as critical for optimal neurological health. While there are eight natural types of vitamin E, α-tocopherol has received the greatest attention as its plasma half-life is 20 hours, which is considerably longer than that of other isoforms. The emphasis on α-tocopherol is possibly due to its similarity to tocopherol transfer protein, which controls the entire body’s status of vitamin E (Galli et al. 2017; Jiang 2014). Because vitamin E is an important micronutrient, people need to take the vitamin to maintain adequate levels. The minimum RDA for α-tocopherol is currently 15 mg/day for adults and the maximum dose is 1,000 mg/day (Shahidi and De Camargo 2016).
Development of gamma-tocotrienol as a radiation medical countermeasure for the acute radiation syndrome: current status and future perspectives
Published in Expert Opinion on Investigational Drugs, 2023
Considering the widespread use and availability in the marketplace of the tocopherol group, including GT3, as nutritional supplements, in cosmetics, and in oral care/hygienic products, they are recognized as safe for various applications in humans, including medicinal purposes [35]. The literature on this subject is extensive, going well beyond the scope of this article, but suffice it to say that GT3/tocopherol is exceedingly well tolerated when administered topically or orally, even at the upper reaches of dose administrations. However, this general statement concerning GT3/tocopherol’s lack of toxic potential is far less certain when these agents are administered by injection. Despite the lack of reports of observing toxic effects associated with GT3/tocopherol administration in small experimental animals, there has been at least one report of adverse effects at the site of GT3 injections of large experimental animals (NHPs) when doses were at 75 mg/kg or greater [36]. Regardless, additional toxicological assessments of injected GT3 are warranted and would encompass both large animal models as well as human volunteers (Phase 1 clinical trials).
A meta-analysis of peripheral tocopherol levels in age-related cognitive decline and Alzheimer’s disease
Published in Nutritional Neuroscience, 2021
Stephanie Ashley, Steven Bradburn, Chris Murgatroyd
Tocopherols have antioxidant and anti-inflammatory properties. Interestingly, there are variations in antioxidant activity between tocopherols with some forms more effective than others at neutralizing some free radicals. Each form also has unique biological functions, linked to variations in immune activity, hypocholesterolemic properties and modulation of different signalling pathways (for review see [5]). Considering the large numbers of studies showing the crucial role of oxidative stress in the development of neurodegenerative disorders (for review see [6]), levels of antioxidants and their supplements have been proposed as preventive measures against dementia. Though, experimental studies indicate that vitamin E exerts beneficial effects in animal models (for review see [7]), its efficacy in AD patients is controversial. For example, one of the earliest double-blind, randomized multicenter clinical trials [8] showed vitamin E slowed AD progression, though several subsequent double-blind study studies such as [9] found vitamin E supplementation had no benefit (for review see [10]). Two recent Cochrane reviews [11,12] were also unable to support evidence for the role of vitamin E supplementation, concluding that the amount and quality of research evidence was limited.
The Potential Physiological Role of γ-Tocopherol in Human Health: A Qualitative Review
Published in Nutrition and Cancer, 2020
Mika D. Thompson, Robert V. Cooney
Tocopherols are lipid-soluble compounds that consist of a chromanol ring and a 16 carbon, phytyl side chain with a varying number of methyl groups on the chromanol ring. Based on the methylation of the chromanol ring, tocopherols are designated as α-, β-, γ-, and δ-tocopherol (Figure 1). For example, γ-tocopherol is dimethylated at the 7- and 8-positions, whereas α-tocopherol is trimethylated at the 5-, 7-, and 8-positions, along the chromanol ring. Naturally occurring tocopherols have three chiral centers in the RRR configuration at the 2, 4, and 8 positions. Tocopherols are typically found in the lipid fractions of seeds and nuts and oils. To the best of our knowledge, there is no up-to-date description of the contemporary γ-tocopherol content of the American diet; however, in the 1970’s, the American diet, relying heavily on corn and soybean oils, has been described as especially high in γ-tocopherol (86). Assuming no decreased intake since the 1970’s means that γ-tocopherol may still constitute the majority of the tocopherols consumed (87). Additionally, walnuts, peanuts, and sesame seeds, along with their oils, are also significant sources of γ-tocopherol in the diet (88).