Bedeutung von Zink für das Immunsystem im Alter

Abstract: During the last years numerous and concurrent observations have been published, which showed that zinc influences the immunological system in a regulating manner. This can happen in a stimulating as well as in an inhibiting way. Especially when zinc becomes effective as a cofactor of enzymatic reactions on the cell surface, in the cell membrane or inside the cell itself, it can have a significant influence on metabolic processes and the cell proliferation. A disturbed immune reaction of the cell and an impaired thymus activity have been repeatedly described with a reduced production of antibodies in connection with a zinc deficiency. The lack of zinc can indicate, depending on the intensity and duration of its existence, a pathobiochemical situation, where it is possible to achieve far-reaching effects also on the immunological defense mechanism.Zinc deficiency as a result of food reduction, long-term parenteral diet, malabsorption, disturbed storage or innate, unclear functional mechanisms leads to an exhaustion of possible reserves, and because of the essentiality in the case of numerous enzymatic reactions, also to immunological changes, which first of all have a subclinical course and can hardly be recognized, but which, in an advanced stage, can lead to immunodeficiencies with infections which can hardly be controlled. The immunological defence including the cellular immunity, the antibody reaction and antibody affinity, the complement system and the phagocyte activity are impaired. In extreme cases, a thymus and lymph node atrophy, a lymphopenia with a reduction of cytotoxic lymphocytes as well as a quotient shifting of the lymphocyte and phagozyte subsets can be observed with a long-term administration of zinc. The result of such serious changes in the structure of the immunological system is a significant functional impairment of the antibody reaction with respect to T cell dependent as well as T cell independent antigens, of the cytolytic T cell reaction, the activity of the natural killer cells (NK cells) and the hypersensitive reaction of the delayed type (DTH delayed type of hypersensitivity).A proven zinc deficiency has to be substituted generally, in the case of an immunodeficiency in combination with a zinc deficiency, the treatment with zinc results in a fast symptomatic improvement of the clinical picture and an objective normalization of the pathobiochemical parameters described. When a reduced zinc level is increased, also the activities of thionin in the case of acrodermatitis or the nucleoside phosphorylase in the case of the sicklecell anemia are normalized. After a respective substitution, the reduced activity of the NK cells can be increased to a normal level. Especially in the convalescent phase after diseases and symptoms which are accompanied by a reduced administration or an increased loss of mineral substances and trace elements and which therefore lead to a latent deficit, a substitution is important because in this phase the cellular immunity is especially burdened.

Keyword(s): Antioxidation

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