Made available in DSpace on 2014-12-17T14:13:36Z (GMT). No. of bitstreams: 1 AnnaCQM.pdf: 331321 bytes, checksum: d4329ae02e1718e26e150e9d4894a746 (MD5) Previous issue date: 2008-06-20 / Although many studies point to alterations in the organic concentrations of zinc in elderly patients, the mechanisms by which aging might cause changes in the metabolism of this nutrient remain unclear. Thus, we assessed the changes in plasma zinc, Zinc Binding Capacity to Plasma Protein (ZnBCPP) and Saturation Index (SI), comparing elderly individuals and young adults. The zinc analyses were performed by atomic absorption spectrophotometry. A statistically significant difference (p < 0.001) was found between the two groups, in relation to plasma zinc and SI, but the ZnBCPP did not differ between the younger and older subjects. In agreement with this result, it was shown in the young group that 76% (R2 = 0.760) of the ZnBCPP variations are explained by the variations in plasma zinc and SI. In the elderly group this measure decreased to 30.5% (R2 = 0.305). We conclude, therefore, that aging may be a factor associated to changes in control mechanisms and in zinc homeostasis, and could even alter ZnBCPP response patterns and other zinc-related indicators of nutritional status. / Embora muitos estudos apontem altera??es nas concentra??es org?nicas de zinco em pacientes idosos, os mecanismos pelos quais o envelhecimento poderia implicar em mudan?as no metabolismo deste nutriente ainda permanecem obscuros. Assim, procuramos avaliar as mudan?as relativas ao zinco plasm?tico, Capacidade de Liga??o do Zinco ? Prote?na Plasm?tica (CLPPZn) e ?ndice de Satura??o (IS). As an?lises de zinco foram realizadas por espectrofotometria de absor??o at?mica, comparando idosos e adultos jovens. Foi encontrada diferen?a estaticamente significante (p<0,001), entre os dois grupos, em rela??o ao zinco plasm?tico e IS, sendo que a CLPPZn n?o diferiu entre os idosos e adultos jovens. Corroborando este resultado, foi demonstrado que, no grupo jovem as varia??es na CLPPZn s?o explicadas em 76% (R2= 0,760) pelas varia??es no zinco plasm?tico e IS. J? no grupo de idosos esta medida diminui para 30,5% (R2= 0,305). Conclu?mos ent?o que o envelhecimento pode ser um fator associado ?s mudan?as nos mecanismos de controle e homeostase do zinco, alterando inclusive padr?es de resposta relativos a CLPPZn e demais indicadores do estado nutricional relativo ao zinco.