Zinc is a mineral important in the protection against free radicals, as a cofactor in vision, energy metabolism, amino acid and protein synthesis. It is essential in proper immune system function, essential for growth in children, proper tissue repair and sexual development. Zinc plays an important role in wound healing and fertility. Since animal proteins are the best sources vegetarians are often deficient.
Zinc may be beneficial in acne, recurrent infections, skin problems and healing, arthritis, stomach ulcer, benign prostatic hyperplasia, vision and osteoporosis.
Published Clinical Studies
Zinc-deficient rats have fewer recent thymic emigrant (CD90+) T lymphocytes in spleen and blood.
Hosea HJ, Rector ES, Taylor CG.
Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada R3T 2N2.
It has been hypothesized that increased expression of the signaling protein p56(lck) disrupts maturation of T lymphocytes, leading to the lymphopenia associated with dietary zinc deficiency and malnutrition. Our objective was to examine p56(lck) protein levels, flow cytometric markers of T cell development (CD4, CD8, TCRalphabeta, TCRgammadelta and CD90) and absolute cell numbers in thymus, spleen and blood of zinc-deficient (ZD), diet-restricted (DR) and control (CTL) rats. Recent thymic emigrant (CD90+) T lymphocytes were also investigated after dietary repletion. P56(lck) protein levels were one- to twofold greater in thymocytes than splenocytes, and ZD rats had more thymocyte p56(lck) protein than CTL rats. In the thymus and blood, the proportions of T lymphocyte subpopulations (CD4-CD8-, CD4+CD8+ and CD4+CD- or CD4-CD8+) were unchanged, except for a higher percentage of TCRalphabeta+CD-CD8+ thymocytes in ZD rats. The 15-29% fewer CD90+ T cells in the blood and spleen of ZD rats were reversed after dietary repletion for 7 and 23 d, respectively. In summary, T-cell numbers were proportional to thymus and spleen weights and unaltered per unit blood volume, despite elevated thymocyte p56(lck) protein in ZD rats. In zinc deficiency, the decreased percentages of CD90+ cells in the blood and spleen could adversely affect the T-cell repertoire.
PMID: 14652378 [PubMed - indexed for MEDLINE]
Diet and nutrition in urologic cancer.
Kamat AM, Lamm DL.
Dept. of Urology, West Virginia University School of Medicine, Morgantown, USA.
Cancer is a major cause of mortality and morbidity throughout the world and is projected to become the leading cause of death in the United States and other developed countries in the next few years. There is a large body of evidence linking diet and nutrition with the development of urologic cancers. This is an area where intervention and education can have a major preventive effect on the occurrence of cancer on a worldwide basis. With bladder cancer, a significant protective effect is conferred by a combination of high doses of vitamins A, B6, C and E plus zinc. For prostate cancer, reduced fat intake has a protective effect. A lesser benefit is also suggested with intake of vitamins D and C. Evidence for chemoprevention against renal cell cancer is supported mainly by epidemiologic studies with animal studies indicating possible benefit of vitamin D supplementation. Further research is needed before vitamins and other nutritional supplements can be advocated as standard therapy. Current data support increased intake of vitamins A, B6, C, D and E, reduction of animal fat and increased intake of fruits and vegetables.
Publication Types:
PMID: 14619137 [PubMed - indexed for MEDLINE]
Oxidative stress, toxic hepatitis, and antioxidants with particular emphasis on zinc.
Stehbens WE.
Department of Pathology and Molecular Medicine, Wellington School of Medicine and Health Sciences, P.O. Box 7343, Wellington South, New Zealand. wstehbens@wnmeds.ac.nz
Hepatic metabolism of biological toxins, industrial poisons, and medicinal agents involves disturbed hepatic cell biochemistry with augmented generation of reactive oxygen species and free radicals and redox imbalance with secondary damage to proteins, nucleic acids, lipids, and carbohydrates. The xenobiotic hepatotoxicity ranging from a subclinical anicteric state to severe necroinflammatory hepatitis (acute, recurrent or chronic) and cirrhosis depends on the nature, dosage, and duration of exposure to the xenobiotic, the antioxidant defence, and concomitant exposure to other diseases or xenobiotics. Experimental and clinical studies suggest that xenobiotic hepatotoxicity with variable depletion of antioxidants can be avoided or ameliorated by administration of an unusually high dosage of zinc or by a combination of antioxidants above normal daily requirements. Therefore reassessment of optimal prophylactic and therapeutic nutritional requirements of antioxidants (particularly zinc) to defend humans against xenobiotic induced oxidative stress is advocated.
Publication Types:
PMID: 14611818 [PubMed - indexed for MEDLINE]
Apoptosis in the normal and inflamed airway epithelium: role of zinc in epithelial protection and procaspase-3 regulation.
Truong-Tran AQ, Grosser D, Ruffin RE, Murgia C, Zalewski PD.
Department of Medicine, University of Adelaide, The Queen Elizabeth Hospital, Woodville, South Australia 5011, Australia.
The epithelium lining the airways is a physical barrier as well as a regulator of physiological and pathological events in the respiratory system. Damage to the epithelium by oxidants released from inflammatory cells is a critical factor in the pathogenesis of airway inflammatory diseases such as bronchial asthma. In these diseases, excessive apoptosis may be a likely mechanism responsible for damage to, and sloughing, of airway epithelial cells. Factors that increase the airway epithelium's resilience to apoptosis are likely to lessen the severity of this disease. One such factor is the dietary metal zinc. A special role for labile intracellular pools of zinc as anti-apoptotic agents in the regulation of the caspases, has emerged over the past two decades. This review focuses on caspase-inhibitory functions of zinc in airway epithelial cells, apparent abnormalities of zinc homeostasis in asthmatics and studies from the authors' laboratory which showed that zinc was strategically localized in the apical cytoplasm of airway epithelium to control caspase-3 activated apoptosis. These findings are discussed in the context of recent data from a murine model of allergic asthma, showing that loss of airway epithelial zinc was accompanied by changes in levels of both procaspase-3 and active caspase-3 and that nutritional zinc deprivation further increased airway epithelial apoptosis. We hypothesize that zinc has a protective role for the airway epithelium against oxyradicals and other noxious agents, with important implications for asthma and other inflammatory diseases where the epithelial barrier is vulnerable and compromised.
Publication Types:
PMID: 14555222 [PubMed - indexed for MEDLINE]
Zinc supplementation and growth of the fetus and low birth weight infant.
Castillo-Duran C, Weisstaub G.
Institute of Nutrition and Food Technology, Universidad de Chile, Macul 5540, Santiago, Chile.
Zinc deficiency limits growth in young children, and in animal models it also affects fetal growth. In animals, the effect of severe zinc deficiency on growth is evident. However, controlled trials of zinc supplementation during pregnancy in humans have not demonstrated consistent effects on weight at birth and/or duration of gestation. Those studies that have identified a positive effect of zinc on fetal growth were performed on low-socioeconomic or migrant groups in industrialized countries or in countries where diet and living conditions are improving. In contrast, in studies conducted either on populations with minimal risk of zinc deficiency or those suffering from multiple and severe nutritional deficiencies, no effects have been found. The potential confounding factors that may help explain the contradictory results include the following: age of pregnant women; presence of digestive diseases, other nutritional deficiencies, phytates or other factors that affect bioavailability; timing and duration of zinc supplementation and compliance with supplements. Few studies of zinc supplementation were conducted on infants that were born small for their gestational age or preterm; in this case, a positive effect on growth was shown. A study of zinc supplementation during pregnancy found reduced risk of diseases (diarrhea or impetigo) in small-for-gestational-age but not preterm infants. A second study demonstrated reduced mortality in small-for-gestational-age infants. We conclude that supplementation trials during human pregnancy do not provide conclusive evidence for a beneficial effect of zinc supplementation despite the experimental evidence that zinc deficiency may retard fetal growth or shorten pregnancy. However, early zinc supplementation in low birth weight or small-for-gestational-age infants reveals an effective improvement in growth, which suggests a prenatal depletion or insufficient zinc intake to support catch-up growth postnatally.
Publication Types:
PMID: 12730451 [PubMed - indexed for MEDLINE]
Nutritional aspect of zinc availability.
Camara F, Amaro MA.
Department of Food Science and Nutrition, University of Cordoba, Campus de Rabanales, Edificio C-1, Carretera N-IV, Km 396 A, 14014 Cordoba, Spain.
Zinc is an essential trace element in human nutrition and its deficiency is a world nutritional problem. However, the zinc content of foods is low and its availability is conditioned by several physiologic and dietary factors. For that reason, the objective of the present work is to compile past and present information about the influence of these factors on zinc availability to try to improve this availability.
Publication Types:
PMID: 12701371 [PubMed - indexed for MEDLINE]
Risk of suboptimal iron and zinc nutriture among adolescent girls in Australia and New Zealand: causes, consequences, and solutions.
Gibson RS, Heath AL, Ferguson EL.
Department of Human Nutrition, University of Otago, Dunedin, New Zealand.
Surveys in Australia, New Zealand and other industrialised countries report that many adolescent girls have dietary intakes of iron and zinc that fail to meet their high physiological requirements for growing body tissues, expanding red cell mass, and onset of menarche. Such dietary inadequacies can be attributed to poor food selection patterns, and low energy intakes. Additional exacerbating non-dietary factors may include high menstrual losses, strenuous exercise, pregnancy, low socioeconomic status and ethnicity. These findings are cause for concern because iron and zinc play essential roles in numerous metabolic functions and are required for optimal growth, immune and cognitive function, work capacity, sexual maturation, and bone mineralization. Moreover, if adolescents enter pregnancy with a compromised iron and zinc status, and continue to receive intakes of iron and zinc that do not meet their increased needs, their poor iron and zinc status could adversely affect the pregnancy outcome. Clearly, intervention strategies may be needed to improve the iron and zinc status of high risk adolescent subgroups in Australia and New Zealand. The recommended treatment for iron deficiency anaemia and moderate zinc deficiency is supplementation. Although dietary intervention is often recommended for treating non-anaemic iron deficiency and mild zinc deficiency, it is probably more effective and appropriate for prevention than for the treatment of suboptimal iron and zinc status. Many of the strategies for enhancing the content and bioavailability of dietary iron are also appropriate for zinc.
Publication Types:
PMID: 12492646 [PubMed - indexed for MEDLINE]
Zinc deficiency in mice alters myelopoiesis and hematopoiesis.
King LE, Fraker PJ.
Department of Biochemistry and Molecular Biology and Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824-1319, USA.
Suboptimal nutriture causes leukopenia, but whether this is related to a modification in hematopoiesis is unknown. A 34-d period of zinc deficiency was used to obtain moderate and severely zinc-deficient (ZD) young adult mice whose bone marrow was evaluated for alterations in hematopoiesis, myelopoiesis and lymphopoiesis by flow cytometry. Expressions of CD31 (PECAM-1) and Ly-6C were used to identify changes in marrow population composition. Identity of marrow cells was confirmed with TER119, CD45R, Ly-6G and CD11b. Cells of the erythroid lineage declined as much as 60% depending on the degree of zinc deficiency, providing new insight into the early observations of clinicians that anemia accompanied ZD in humans. The lymphoid compartment also declined 50-70% with preferential losses among pre-B cells, an underlying cause of the lymphopenia that is a part of ZD, in which loss of pre-B cells was identified by CD43,CD45R, and immunoglobulin M. Conversely, cells of the myeloid lineage increased substantially in the marrow, both in proportion and absolute numbers in all ZD mice. Granulocytic cells increased 40-60%, whereas monocytic cells nearly doubled in ZD mice. These data suggest that there are important adaptations in hematopoietic functions as zinc becomes limiting. In the immune system, the precursors of phagocytic cells, which provide innate immunity, are protected, whereas precursors of lymphocytes, which provide adaptive immunity, are down-regulated. These findings illuminate the unique response of the marrow to a nutritional stress.
PMID: 12421843 [PubMed - indexed for MEDLINE]
Mohan H, Verma J, Singh I, et al. Inter-relationship of zinc levels in serum and semen in oligospermic infertile patients and fertile males. Indian J Pathol Microbiol 1997;40:451-5.