Vitamin A deficiency. New knowledge on diagnosis, consequences and therapy

Due to the rapid development of biochemical analyses in the last 10 years different substances like vitamin A, with an apparent clarified metabolism and action, were re-estimated. As a result, new knowledge was presented which could be essential for human health. Some details and consequences are reviewed in this paper. Marginal deficiency, which also may occur in industrialized nations, cannot be determined with certainty by usual blood analyses. The reasons for marginal deficiency are either different diseases or unbalanced nutrition. From epidemiological research it is argued that low vitamin A intake is associated with a higher incidence of cancer in different tissues. However, vitamin …