[Zinc and vitamin A deficiency in gastrointestinal diseases].

It has been established rather surely that patients with chronic liver disease, Crohn's disease, chronic pancreatis and celiac disease are deficient in zinc and vitamin A. A large number of clinical symptoms can be caused by these deficiencies, due to the fact that these compounds have numerous functions. Zinc deficiency in liver cirrhosis is probably caused by portosystemic shunting, whereas in Crohn's disease abnormalities of protein metabolism are suggested as etiologic factor. Vitamin A deficiency can be considered as a consequence of disturbed zinc metabolism. Some studies in appropriate patients receiving substitution therapy with zinc and/or vitamin A had positive results. However, the necessity of substitution in the diseases mentioned has not yet been conclusively demonstrated.