Vitamin E

Not only a single stereoisomer

authored by: M. Eggersdorfer, K. Schmidt, S. Péter, J. Richards, B. Winklhofer-Roob, A. Hahn, U. Obermüller-Jevic
Abstract: The recent publication by Azzi and colleagues puts forth the argument that only RRR-α-tocopherol should be considered as vitamin E from a physiological point of view. They base their argument primarily on the assertion that only this form has been used to treat stark vitamin E deficiency in humans (known as AVED, or Ataxia with Vitamin E Deficiency). Azzi et al. also argue that other chemically similar molecules, such as tocopherols other than α-tocopherol and tocotrienols do not provide vitamin E activity. Azzi and colleagues are correct on this second point. An investigation into the biological activities of vitamin E, and the mechanisms behind these activities, confirms that physiological vitamin E activity is limited to certain α-tocopherol forms. However, it is also clear that these activities are not restricted only to the RRR-form but include other 2R-forms as well. Indeed, the α-tocopherol transfer protein (α-TTP), which is critical to mediate vitamin E trafficking and biological activity, and genetic defects of which lead to vitamin E deficiency, binds well to all 2R-forms of α-tocopherol. Furthermore, both RRR-α-tocopherol and the other 2R-forms are maintained in human plasma and distributed to tissues and organs, whereas the 2S-stereoisomers are excreted quickly. As such, in recent years the definition of vitamin E including both 2R- and RRR-α-tocopherol has gained both broad scientific and regulatory acceptance. Consistent with this understanding, we provide evidence that AVED has indeed been treated successfully with forms in addition to RRR-α-tocopherol, again arguing against the restriction of the definition to RRR-α-tocopherol only. Finally, we provide evidence against any safety concerns utilizing the currently accepted definition of vitamin E.
Organisation(s): Institute of Food Science and Human Nutrition
Nutrition Physiology and Human Nutrition Section
External Organisation(s): University of Groningen
University of Tübingen
University of Graz
BASF SE
dsm-firmenich
Type: Article
Journal: Free Radical Biology and Medicine
Volume: 215
Pages: 106-111
No. of pages: 6
ISSN: 0891-5849
Publication date: 03.2024
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Biochemistry, Physiology (medical)
Electronic version(s): https://doi.org/10.1016/j.freeradbiomed.2024.02.013 (Access: Closed)

BibTeX

@article{d2be9e57300a45589fc8b42abc02ce47,
title = "Vitamin E: Not only a single stereoisomer",
abstract = "The recent publication by Azzi and colleagues puts forth the argument that only RRR-α-tocopherol should be considered as vitamin E from a physiological point of view. They base their argument primarily on the assertion that only this form has been used to treat stark vitamin E deficiency in humans (known as AVED, or Ataxia with Vitamin E Deficiency). Azzi et al. also argue that other chemically similar molecules, such as tocopherols other than α-tocopherol and tocotrienols do not provide vitamin E activity. Azzi and colleagues are correct on this second point. An investigation into the biological activities of vitamin E, and the mechanisms behind these activities, confirms that physiological vitamin E activity is limited to certain α-tocopherol forms. However, it is also clear that these activities are not restricted only to the RRR-form but include other 2R-forms as well. Indeed, the α-tocopherol transfer protein (α-TTP), which is critical to mediate vitamin E trafficking and biological activity, and genetic defects of which lead to vitamin E deficiency, binds well to all 2R-forms of α-tocopherol. Furthermore, both RRR-α-tocopherol and the other 2R-forms are maintained in human plasma and distributed to tissues and organs, whereas the 2S-stereoisomers are excreted quickly. As such, in recent years the definition of vitamin E including both 2R- and RRR-α-tocopherol has gained both broad scientific and regulatory acceptance. Consistent with this understanding, we provide evidence that AVED has indeed been treated successfully with forms in addition to RRR-α-tocopherol, again arguing against the restriction of the definition to RRR-α-tocopherol only. Finally, we provide evidence against any safety concerns utilizing the currently accepted definition of vitamin E.",
author = "M. Eggersdorfer and K. Schmidt and S. P{\'e}ter and J. Richards and B. Winklhofer-Roob and A. Hahn and U. Oberm{\"u}ller-Jevic",
year = "2024",
month = mar,
doi = "10.1016/j.freeradbiomed.2024.02.013",
language = "English",
volume = "215",
pages = "106--111",
journal = "Free Radical Biology and Medicine",
issn = "0891-5849",
publisher = "Elsevier Inc.",
}