Vitamine und Mineralien

Vitamin A Metabolism: Challenges and Perspectives

Abstract

Ouliana Ziouzenkova

Vitamins set an unprecedented example of the essential environment-gene interactions that are necessary to sustain life. Seventeen Nobel prizes were awarded in the last century for discoveries related to vitamins’ structures, physiology, and functions [1]. These discoveries help to abolish diseases related to vitamin deficiencies in the developed world and offer solutions to eradicate these disorders worldwide [2]. For example, embryonic malformations, night blindness, and immune deficiency in children were effectively treated by vitamin A supplementation [2,3]. In spite of encouraging results in vitamin-deficient subjects, wide applications of vitamin supplements in the nutrient-sufficient populations have been partially discouraging. Many clinical and supplementation trials reported increased mortality in subjects on long-term lipophilic vitamin A and E supplementations [4,5]. Especially striking deleterious effects were reported for lipophilic vitamin A and provitamin A (β-carotene) [4,6]. The answer to safe application of lipophilic vitamins for the treatment and prevention of diseases may lie in the better understanding of their interaction with genes. There are two principal levels of lipophilic vitamin interactions with genes:

1) genes control metabolism of dietary vitamin into derivatives with hormone-like properties, and

2) vitamin-derived metabolites regulate specific gene programs through signaling and transcription pathways (Figure1).