The role of zinc in health and disease: relevance to child health in developing countries.
Year: 1997
Type: article
Abstract: The last few years have witnessed the earnest recognition of the vital role of micronutrients in human health.The pioneering work by Sommers et al 1 in Indonesia on the impact of vitamin A supplementation in young children with respiratoty infections, has led to a host of experiments evaluating the impact of both clinical and subclinical deficiency of micronutrients on child survival 2 .Of the micronutrients, in addition to vitamin A and iron, zinc stands out as the one with the greatest potential public health impact.Although, compared to other micronutrients, zinc status is considerably more difficult to assess in humans 3 , its biological effects in malnourished children are diverse, ranging from a profound impact on growth 4 , to a significant role in regulation of immunity 5 .This review will focus on cunent concepts of the biological effects of zinc, with special reference to its potential role in the paediatric age group in Pakistan. Role of Zinc in iluman GrowthThe importance of zinc in biological systems was recognized as early as 1869 by Raulin during studies on Aspergillus niger 6 .Although the importance of zinc in animals had been established 7,8 , human zinc deficiency was first described by Prasad in 1961 9 .Since then, the importance of zinc in human metabolism and growth in both health and disease has become well established 10 .It is currently known that over 200 zinc metalloenzymes exist in the human body 11 .Of these, many e.g., carbonic anhydrase, alkaline phosphatase, carboxypeptidase A,B etc., perfonn a variety of vital functions.However, zinc deficiency does not exert its effects through deficient function of these enzymes alone.Zinc also performs a vital biological role in maintenance of biomembranes 12 and is also considered essential for DNA replication, transcription and translation 13 .Other important roles attributed to zinc include maintenance of adequate immune function 14 and brain development 15 .Our knowledge on the scope and contribution of zinc nutrition to paediatric physiology has widencd considerably since the initial limitation to six clinical 'syndromes' 16 and zinc is .nowconsidered crucial to the maintenance of satisfactory growth in childhood.Zinc deficiency has been shown to effect the function of human growth hormone by modulating with the function of the polypeptide hormone-receptor 'zinc sandwich, 17 This could provide a mechanism to explain the close relationship between alteration in zinc nutriture and plasma insulin-like growth factors (Somatomedin C) 18,19 .A growth limiting mild zinc deficiency state has been described in young boys with short stature 20 .Although initial studies of zinc supplementation of the diet failed to show any significantly, greater effect on growth 21 and appetite 22 , other studies of zinc supplementation have shown to significantly improve the linear ;rowth and weight gain of preschool children with stunting 3,24 , Role of zinc in intrauterine growth and lactation The essential role of zinc in the maintenance of structure of biomembranes 12 , DNA and RNA synthesis 13 and metabolism of essential fatty acids 25 , makes it an extremely important micronutrient in pregnancy 26 .A close association has been found between zinc status and normal fetal growth [27][28][29][30] and abnormal zinc nutriture has also been associated with an increased rate of malformations 31,32 and premature rupture of membranes 33 .Ofparticularinterest is the association between low maternal levels of zinc and intrauterine growth retardation (IUGR) 34,35 .Although some studies have failed to show a
Source: PubMed
Author: Z A Bhutta
Institution: Aga Khan University
Language: English
Topic: Trace Elements in Health
Subfield: Nutrition and Dietetics
Field: Nursing
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2303364703