Immunobiology of gestational zinc deficiency

The trace element zinc is an essential micronutrient for the proper functio ning of the immune system. Zinc deficiency leads to impaired function of th e unspecific and specific immune response and consequently to an increased susceptibility to bacterial, viral and fungal infections. Immunological def ects are not only seen in pronounced but even in marginal and moderate zinc deficiency. Lack of zinc is especially harmful for the development of the immune system, which stresses the importance of a balanced zinc level durin g pregnancy. However, gestational zinc deficiency due to an imbalance betwe en intake and increased requirements is a common problem world-wide. In ani mals, gestational zinc deficiency results in reduced thymic and spleen size and depressed active and passive immunity in the infant. For example, depr essed immunoglobulin levels, altered antibody repertoire, reduced prolifera tive response of lymphocytes and diminished neutrophil functions have been reported. Interestingly, immune defects caused by prenatal zinc deficiency, such as depressed antibody levels and lymphocyte proliferation, may even p ersist in subsequent generations and are not reversible by postnatal zinc a dministration. Since gestational zinc deficiency is a common problem throug hout all cultures and socioeconomic levels, it might have immense consequen ces for the health status of the population. Based on a summary of the immu nobiology of zinc, this article reviews the significance of zinc deficiency during pregnancy and the effect of gestational zinc deficiency on passive and active immunity in the infant. It provides a rational basis for both im munological laboratory investigations and field studies, such as large comm unity-based zinc supplementation trials in pregnant women.