Human nutritional relevance and suggested nutritional guidelines for vitamin A5/X and provitamin A5/X.

Autor: Bohn T; Nutrition Research Group, Department of Precision Health, Luxembourg Institute and Health, 1 A-B, Rue Thomas Edison, 1445, Strassen, Luxembourg., Hellman-Regen J; Department of Psychiatry, Charité-Campus Benjamin Franklin, Section Neurobiology, University Medicine Berlin, Berlin, Germany., de Lera AR; Departamento de Química Orgánica, Facultad de Química, CINBIO and IBIV, Universidade de Vigo, Campus As Lagoas-Marcosende, 36310, Vigo, Spain., Böhm V; Institute of Nutritional Sciences, Friedrich Schiller University Jena, Jena, Germany., Rühl R; CISCAREX UG, Transvaalstr. 27c, 13351, Berlin, Germany. ralphruehl@web.de.
Jazyk: angličtina
Zdroj: Nutrition & metabolism [Nutr Metab (Lond)] 2023 Aug 15; Vol. 20 (1), pp. 34. Date of Electronic Publication: 2023 Aug 15.
DOI: 10.1186/s12986-023-00750-3
Abstrakt: In the last century, vitamin A was identified that included the nutritional relevant vitamin A1 / provitamin A1, as well as the vitamin A2 pathway concept. Globally, nutritional guidelines have focused on vitamin A1 with simplified recommendations and calculations based solely on vitamin A. The vitamin A / provitamin A terminology described vitamin A with respect to acting as a precursor of 11-cis-retinal, the chromophore of the visual pigment, as well as retinoic acid(s), being ligand(s) of the nuclear hormone receptors retinoic acid receptors (RARs) α, β and γ. All-trans-retinoic acid was conclusively shown to be the endogenous RAR ligand, while the concept of its isomer 9-cis-retinoic acid, being "the" endogenous ligand of the retinoid-X receptors (RXRs), remained inconclusive. Recently, 9-cis-13,14-dihydroretinoic acid was conclusively reported as an endogenous RXR ligand, and a direct nutritional precursor was postulated in 2018 and further confirmed by Rühl, Krezel and de Lera in 2021. This was further termed vitamin A5/X / provitamin A5/X. In this review, a new vitamin A5/X / provitamin A5/X concept is conceptualized in parallel to the vitamin A(1) / provitamin A(1) concept for daily dietary intake and towards dietary guidelines, with a focus on the existing national and international regulations for the physiological and nutritional relevance of vitamin A5/X. The aim of this review is to summarize available evidence and to emphasize gaps of knowledge regarding vitamin A5/X, based on new and older studies and proposed future directions as well as to stimulate and propose adapted nutritional regulations.
(© 2023. BioMed Central Ltd., part of Springer Nature.)
Databáze: MEDLINE
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