Influência do zinco no desempenho muscular em mulheres jovens e idosas

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(1)MINISTÉRIO DA EDUCAÇÃO UNIVERSIDADE FEDERAL DO RIO GRANDE DO NORTE CENTRO DE CIÊNCIAS DA SAÚDE PROGRAMA DE PÓS-GRADUAÇÃO EM CIÊNCIAS DA SAÚDE. EFETIVIDADE DA SUPLEMENTAÇÃO DE ZINCO NA FORÇA, RESISTÊNCIA E EQUILÍBRIO MUSCULAR EM IDOSAS: ensaio clínico randomizado duplo cego. MARIA APARECIDA BEZERRA. NATAL/RN 2013.

(2) MARIA APARECIDA BEZERRA. EFETIVIDADE DA SUPLEMENTAÇÃO DE ZINCO NA FORÇA, RESISTÊNCIA E EQUILÍBRIO MUSCULAR EM IDOSAS: ensaio clínico randomizado duplo cego. Dissertação apresentada ao Programa de PósGraduação em Ciências da Saúde da Universidade Federal do Rio Grande do Norte, como requisito para obtenção do Título de Doutor em Ciências da Saúde. Orientador: Prof. Dr. José Brandão Neto Coordenadora: Profa. Dra. Ivonete Batista Araújo. NATAL/RN 2013.

(3) B574i Bezerra, Maria Aparecida. Influência do zinco no desempenho muscular em mulheres jovens e idosas / Maria Aparecida Bezerra. – Natal/RN, 2013. 57f.: il. Orientador: Prof. Dr. José Brandão Neto Tese (Doutorado em Ciências da Saúde) – Programa de PósGraduação em Ciências da Saúde. Universidade Federal do Rio Grande do Norte. Centro de Ciências da Saúde. 1. Envelhecimento – Tese. 2. Nutrição – Zinco – Tese. 3. Força muscular – Tese. I. Brandão Neto, José. II. Título. RN/UF/BSA01. CDU: 613.2-055.2.

(4) MARIA APARECIDA BEZERRA. EFETIVIDADE DA SUPLEMENTAÇÃO DE ZINCO NA FORÇA, RESISTÊNCIA E EQUILÍBRIO MUSCULAR EM IDOSAS: ensaio clínico randomizado duplo cego. Aprovada em: ______/______/______. BANCA EXAMINADORA. ______________________________________________________________ Prof. Dr. José Brandão Neto (Presidente – UFRN). ______________________________________________________________ Profa. Dra. Selma Sousa Bruno (Membro Interno – UFRN). ______________________________________________________________ Prof. Dr. Eryvaldo Sócrates Tabosa do Egito (Membro Interno – UFRN). ______________________________________________________________ Profa. Dra. Margareth de Fátima Formiga Melo Diniz (Membro Externo – UFPB). _____________________________________________________________ Prof. Dr. Eduardo Sérgio Soares Sousa (Membro Externo – UFPB). ii.

(5) A Deus, fonte de sabedoria, de amor e de inspiração criadora. A Ele dedico este trabalho. Aos meus pais, João (in memoriam) e Irene, pelo esforço que fizeram para que os filhos pudessem estudar. Aos meus amados filhos, Amanda e Tiago, pelas palavras e ações de incentivo quando eu retornava para casa cansada da jornada de trabalho. Às mulheres que fizeram parte dessa pesquisa, pelo compromisso assumido em todas as fases do trabalho e por tudo o que aprendi com elas. Aos Mestres do passado e do presente pelo árduo trabalho com a fonte do conhecimento que pode propiciar o desenvolvimento da humanidade. iii.

(6) AGRADECIMENTOS. A Deus, fonte de vida e amor, que me amparou durante todas as etapas deste trabalho.. Ao Prof. Dr. José Brandão Neto, minha profunda gratidão, pela precisa e preciosa orientação ao longo desta importante fase de minha vida.. A Profa. Áurea Nogueira de Melo por sua dedicação voluntária à avaliação neurológica das pacientes, em todas as fases da pesquisa.. Aos colegas: Naira Josele Neves de Brito, Érika Dantas de Medeiros Rocha, Alfredo de Araújo Silva e Denise Dal'Ava Augusto pela ajuda nos procedimentos de avaliação em suas respectivas áreas de atuação.. À FAPERN e CNPq pelo financiamento da pesquisa.. Ao PPGCSA e aos docentes a ele vinculados.. A UFPB, especialmente aos colegas do Departamento de Fisioterapia, pelo incentivo nesta etapa acadêmica.. Às equipes do Programa de Saúde da Família dos Bancários, Timbó I e Timbó II pelo acolhimento, compromisso e dedicação com que nos receberam e acompanharam durante toda esta pesquisa.. Às voluntárias, cuja colaboração permitiu a realização deste trabalho.. A todos os que, direta ou indiretamente, contribuíram para a conclusão deste trabalho, a minha gratidão.. iv.

(7) RESUMO. Introdução: O decréscimo na função muscular durante o envelhecimento limita a capacidade funcional e, consequentemente, a independência física. Objetivo: Avaliar a efetividade do zinco na força, na resistência e no equilíbrio muscular em mulheres idosas atendidas em área de abrangência da Unidade de Saúde da Família do Sistema Único de Saúde. Metodologia: Ensaio clínico randomizado duplo cego placebo controlado com 38 participantes aleatoriamente distribuídos em 4 grupos: grupo-controle composto por 18 mulheres jovens, com idade entre os 20 e os 30 anos, assim subdivido: Jovem Placebo (n=9) ingeriu placebo (sorbitol 10%); Jovem Zinco (n=9) ingeriu 25mg do elemento zinco. Grupo experimental composto por 20 mulheres idosas, com idade entre os 60 e os 80 anos e subdividido: Idosa Placebo: (n=10) ingeriu placebo; Idosa Zinco (n=10) ingeriu 25mg do elemento zinco. O seguimento teve duração de 90 dias. A força, a resistência e o equilíbrio muscular foram estimados pelo pico de torque isocinético normalizado pelo peso corporal, do quadríceps (PT/kg QUA) e dos isquiotibiais (PT/kg IQS) nas velocidades angulares de 60°/s e de 180°/s por dinamometria Isocinética. Resultados: Na medida inicial PT/kg IQS 60°/s, não houve diferença significativa entre os grupos. Após 90 dias ocorreu redução significativa da força apenas no grupo Idosa Placebo: PT/kg IQS 60°/s =58,53±16,37 Nm em relação ao grupo Jovem Placebo: PT/kg IQS 60°/s = 84,15±27,60 Nm p=0,01. Quanto à resistência dos isquiotibiais (PT/kg IQS 180°/s), os dois grupos de idosas (Placebo e Zinco) eram significativamente menores do que o grupo Jovem Placebo na medida inicial. Após 90 dias, apenas o grupo Idosa Placebo tinha resistência significativa menor que o grupo Jovem Placebo. Efeito dentro de cada grupo: ocorreu aumento significativo de força e resistência dos isquiotibiais no grupo Idosa Zinco e diminuição significativa no grupo Idosa Placebo. A diferença de médias (Δ) entre Idosa Zinco e Idosa Placebo (teste t independente) dos isquiotibiais, após 90 dias, foi significativa tanto para força (PT/kg IQS60°/s Δ=8,97 Nm, p= 0,02) como para resistência (PT/kg IQS 180°/s Δ=11,88 Nm p=0,01). Conclusões: A diferença significativa entre as médias do inicio e as de seguimento, tanto de força como de resistência dos isquiotibiais entre Idosa Zinco e Idosa Placebo, mostra a vulnerabilidade desse músculo durante o envelhecimento. Essas perdas poderiam ser minimizadas com a suplementação de zinco. Isso indica que a nutrição adequada de zinco pode prevenir perda de força e resistência muscular em mulheres com mais de 60 anos.. Descritores: Envelhecimento. Zinco.Nutrição. Força muscular. Dinamômetro de força muscular.. v.

(8) LISTA DE ABREVIATURAS E SIGLAS. ERO. Espécie reativa de oxigênio. DMO. Densidade mineral óssea. Zn. Zinco. Nm. Newton metro. PT. Pico de torque. vi.

(9) SUMÁRIO. 1 INTRODUÇÃO ...................................................................................................... 08 2JUSTIFICATIVA .................................................................................................... 12 3 OBJETIVOS ......................................................................................................... 13 3.1 Objetivo geral .................................................................................................... 13 3.2 Objetivos específicos ........................................................................................ 13 4 MÉTODO .............................................................................................................. 14 5 ANEXAÇÃO DO ARTIGO1 .................................................................................. 15 6 ANEXAÇÃO DO ARTIGO 2 ................................................................................. 40 7 COMENTÁRIOS, CRÍTICAS E CONCLUSÕES. .................................................. 45 REFERÊNCIAS ....................................................................................................... 48 ANEXO ................................................................................................................... 51 APÊNDICE ............................................................................................................. 52. vii.

(10) 8. 1 INTRODUÇÃO. O envelhecimento populacional é uma realidade em países desenvolvidos e em. desenvolvimento(1).. A. prevalência. de. múltiplas. condições. crônicas. e. incapacidade funcional são mais elevadas na senescência. Variações nas condições de saúde, no bem-estar, na capacidade funcional e nas necessidades de cuidado distinguem diferentes grupos de idosos. Tais variações poderão culminar com a Síndrome da Fragilidade caracterizada pela diminuição da massa corporal, fraqueza, fadiga, inatividade, redução da ingestão alimentar, sarcopenia, osteopenia, anormalidades no equilíbrio e na marcha(2). Essas características estão direta ou indiretamente interligadas com fatores,. como:. características demográficas,. socioeconômicas e outros aspectos relacionados com a saúde(3). Estilo de vida sedentário, característico dessa população, está associado com osteoartrite, consequente da inatividade física, redução da função mitocondrial, desajuste do estado redox celular, aumento de inflamação crônica sistêmica que torna o ambiente intracelular do músculo propenso à toxicidade de espécies reativas de oxigênio (ERO)(4). Esses fatores podem contribuir para a redução da massa muscular esquelética. Tal redução tem inicio discreto na terceira década e diminuição significativaa partir do final da quinta década em homens e mulheres(5). A diminuição do músculo esquelético, tecido metabolicamente ativo, afeta a sua. capacidade. metabólica,. particularmente. as. capacidades. glicolíticas. e. respirátórias(6), potencializa aumento da gordura corporal, diminuição da aptidão aeróbica, da massa magra e da densidade mineral óssea(7). Estudo de nosso grupo de pesquisa mostrou que 20,2% da variabilidade da densidade mineral óssea na coluna lombar estava relacionada com a massa magra e tempo de menopausa; 22,3% de variabilidade da densidade mineral óssea do colo do fémur estava relacionada com o peso corporal e idade; 18,9% da variabilidade da densidade mineral óssea no triângulo de Ward estavam relacionadas com a idade e gasto energético basal; e 39% da variabilidade da densidade mineral no trocanter estavam relacionadas com o índice de massa corporal, idade e menarca (8). Essas evidências mostram que o organismo humano reage de forma específica aos diferentes tipos de estímulo, ao longo do desenvolvimento, revelado.

(11) 9. no bidirecional processo epigenético: de genótipo para fenótipo e de fenótipo para genótipo(9). O músculo esquelético sintetiza esse contexto e responde, de acordo com a tipologia de suas fibras, ao metabolismo aeróbico e anaeróbico. Fibras musculares de contração lenta (tipo I) têm metabolismo oxidativo e são ricas em capilares e mitocondrias. São requisitadas durante exercícios que aumentam a resistência muscualar. As fibras musclares de contração rápida (tipo IIa) têm perfil metabólico semelhante às fibras do tipo I. As fibras musculares glicolíticas de metabolismo anaeróbico (tipo IId e IIb) têm pouca mitocondria e pouca vascularização capilar. Estão envolvidas nos exercícios que visam aumentam a força muscular(10). O grupos musclares isquitibias e quadricepes, que são objetos de nosso estudo, apresentam um percentual elevado de fibras musculares de contração rápida tipo II. Em estudo histoquimico, Garrett et al.(11) mostram que há uma proporção maior dessas fibras nos isquitibiais em comparação com o quadriceps. No bícepes femoral (cabeça longa), na área proximal, há um pencentual de 55,2% e na área distal, 53,8%; na cabeça curta do bíceps, na área central, o percentual é de 59,2%;. no semitedinoso, na área proximal, 54,6% e na área distal, 60,4%; no. semimembranoso, na área proximal, 51% e na área distal, de 50,5%. Para o quadríceps, no mesmo estudo, os músculos foram analisados apenas na área central. Mostra portanto, um percentual de fibras musculares tipo II no vasto lateral de 54,5%, no vasto intermédio de 45,7%, no vasto medial de 49,4% e no reto femoral de 57,7%(11). Os músculos com elevado percentual de fibras do tipo II são recrutados em exercício de alta intensidade e geram elevados níveis de tensão nos tendões produzidos por força de estiramento os quais podem expor os músculos a danos em períodos de atividade muscular intensa(11). No envelhecimento a tendência ao dano muscular aumenta, principalmente em mulheres, em decorência do. aumento da. tensão isotônica, da baixa cinética das pontes cruzadas de actina e miosina. Estes danos musculares que têm como consequência maior rigidez muscular e baixa produção de força(12). Isso pode ser agravado devido à característica das fibras musculares glicolícas tipo II que são mais suscetíveis também ao dano provocado por alto nível de estresse oxidativo(10)..

(12) 10. Pessoas idosas com mais de 40% de fibras musculares tipo II apresentaram níveis mais baixos de peroxidação lipídica e desencadeiaram com mais eficiência o sistema contra ânio superóxido do que das pessoas que têm menos de 40% dessas fibras musculares(13). Também é reportado que há redução significativa da força muscular, da área de secção transversa muscular, diminuição de fibras tipo I e decréscimo de capilares por área de fibra muscular (14). Essas transformações biológicas causadas por estilo de vida sedentário e fatores nutricionais podem mudar a capacidade mitocondrial e interferir no metabolismo oxidativo energético, o que pode tornar o organismo vulnerável a agentes agressores celulares, como os radicais livres, principalmente no envelhecimento, os quais estão relacionados com a sarcopenia e doenças crônicas (4, 12). . O estilo de vida fisicamente ativo das pessoas idosas, está associado com a. compensação parcial da preservação da biogênese mitocondrial e com a capacidade antioxidante no músculo esquelético que pode retardar o início da sarcopenia(4). A sarcopenia (redução da massa muscular) e a dinapenia (redução da força muscular) estão associadas com o aumento do estresse oxidativo e podem ser potencializadas devido à menor atividade das enzimas anaeróbicas e aeróbicas, do conteúdo de proteínas, e não apenas devido à diminuição da atividade física(6). Existem evidências de que a deficiência de zinco no organismo pode afetar a função do músculo estriado. (15). e pode induzir a apoptose de células musculares. lisas vasculares. O estresse oxidativo, na deficiência de zinco, contribuiria para a apopitose dessas células(16). Estudos sobre a ação do zinco na saúde humana mostram avanços nesses ultimos 50 anos. Segundo Prasad(17), no início da década de 1960, eram conhecidadas apenas três enzimas que necessitavam de zinco para suas atividades. Atualmente, são conhecidas mais de trezentas enzimas e mais de mil fatores de transcrição que precisam de zinco para realizarem suas atividades. O zinco mostrou ser efetivo para tratar diarréia aguda em crianças e resfriados comuns; prevenir cegueira de pessoas com degeneração macular e reduzir a incidências de infecções no envelhecimento(17)..

(13) 11. O zinco é um abundante elemento de transição no cérebro, tem importante papel na estabilização da proteína básica de mielina e na formação da bainha de mielina(18), está envolvido no desenvolvimento e preservação das funções dos nervos periféricos(19), na preservação da quantidade de fibras musculares e no metabolismo energético dessas fibras musculares(20). Já mostrou exercer influência no trabalho total isocinético dos músculos extensores do ombro e do joelho em homens jovens(21). Durante prolongados períodos de restrição de atividade motora, parece que são modificados mecanismos endógenos da homeostase do zinco. Zorbas et al.(22) mostram. que. ratos. mantidos. em. hipocinesia,. mesmo. estes. recebendo. suplementação de zinco na dieta, esta não garantiu que o zinco penetrasse nos tecidos onde são normalmente depositados, como ocorre nos ossos e nos músculos. Foi obervado também aumento do zinco no plasma, na excreção fecal e urinária, o que resultou em significante perda de zinco corporal(22). Considerando a importância da nutrição de zinco associado com estilo de vida ativo, a pesquisadora propôs essa pesquisa com a finalidade de estudar a influência do zinco na força, na resistência e no equilíbrio muscular em mulheres idosas sadias..

(14) 12. 2 JUSTIFICATIVA A redução do desempenho muscular em homens e mulheres está associada com a sarcopenia, que é uma das principais causas da redução da força e do desempenho muscular no envelhecimento(23) e que é caracterizada pela redução do número, do tamanho e do nível da vascularização das fibras musculares (13). A estimativa de sarcopenia aumenta à medida que as pessoas envelhecem. Em pessoas com idade entre os 60 e os 70 anos, o percentual de sarcopenia fica entre 5% e 13%. Já em pessoas com mais de 80 anos, essa estimativa aumenta para os percentuais de 11% a 50%(24). A diminuição da força muscular relacionada com a idade foi denominada dinapenia. em. 2008(25).. Ela. tem. consequência. significativa,. durante. o. envelhecimento, por aumentar o risco de limitações funcionais, de incapacidade e de mortalidade(26). É reportado atualmente que a dinapenia do quadríceps e do punho e não a sarcopenia, é preditor independentes de mortalidade(27). O estudo da dinapenia em mulheres é um tema que tem relevância clínica, por ser fator de risco para a maioria das doenças crônicas relacionadas com o envelhecimento. Por outro lado, um aporte suplementar de zinco pode favorecer aumento da força muscular devido sua ação como antioxidante, estimulante imunológico e como agente inflamatório(16). Considerando a realidade do decréscimo do desempenho muscular no envelhecimento e sua associação com a nutrição adequada de zinco, o presente estudo investigou a efetividade da suplementação de zinco (25 mg do elemento Zn++) no aumento da força, da resistência e do equilíbrio entre os músculos isquiotibiais e quadríceps em mulheres jovens e idosas. Portanto, este projeto atendeu à finalidade primordial da Política Nacional de Saúde da Pessoa Idosa (Portaria nº 2.528 de 19 de outubro de 2006)(28). Tal política visa a “recuperar, manter e promover a autonomia e a independência dos indivíduos idosos” por estar inserido o projeto na Atenção Básica de Saúde, em consonância com os princípios e diretrizes do Sistema Único de Saúde..

(15) 13. 3 OBJETIVOS 3.1 Objetivo geral. Avaliar a efetividade do zinco (25 mg do elemento Zn++) no desempenho dos músculos isquiotibiais e dos quadríceps nas velocidades angulares de 60°/s e de 180°/s entre mulheres jovens e idosas.. 3.2 Objetivos específicos. Verificar se a suplementação de zinco em mulheres idosas diminuiu a diferença de força e resistência, em comparação com as mulheres jovens.. Observar se a suplementação de zinco aumentou a força, resistência e equilíbrio muscular em mulheres idosas.. Constatar se houve diferença significativa entre as mulheres idosas que foram suplementadas com zinco e aquelas que ingeriram placebo..

(16) 14. 4 MÉTODO. Ensaio clínico randomizado duplo cego placebo controlado com um seguimento de sessenta dias. Trinta e oito mulheres foram distribuídas, aleatoriamente, em quatro grupos. O grupo-controle foi constituído por 18 mulheres jovens com idade entre os 20 e os 30 anos e subdivido em dois grupos: Jovem Placebo (n=9) ingeriu placebo (sorbitol 10%) e Jovem Zinco (n=9) ingeriu 25 mg do elemento zinco. O grupo experimental foi composto de 20 mulheres idosas com idade entre os 60 e os 80 anos, subdividido em dois grupos: Idosa Placebo (n=10) ingeriu placebo e Idosa Zinco (n=10) ingeriu 25 mg do elemento zinco. A força, a resistência e o equilíbrio muscular foram estimados pelo torque isocinético normalizado pelo peso corporal do quadríceps e dos isquiotibiais nas velocidades angulares de 60°/s e de 180°/s, antes e após os sessenta dias de tratamento..

(17) 15. 5 ANEXAÇÃO DO ARTIGO 1 ARTIGO 1 Título: Efetividade da suplementação de zinco na força, na resistência e no equilíbrio muscular em mulheres idosas: ensaio clínico randomizado duplo cego. Periódico: Clinical Interventions in aging ISSN: 1176-9092 (Print) Qualis: A2 (Medicina II – CAPES) Fator de impacto: 2.083 Status: a ser submetido.

(18) 16. ORIGINAL RESEARCH. Clinical Interventions in aging. Effectiveness of zinc supplementation on strength, endurance, and muscle balance in elderly women: a randomized double blind clinical trial.. Maria Aparecida Bezerra1 Simone Bezerra Alves1 Áurea Nogueira de Melo2 Érika Dantas de Medeiros Rocha3 Naira Neves de Brito3 José Brandão-Neto4. 1. Departamento de Fisioterapia da Universidade Federal da Paraíba (João Pessoa,. Brasil); 2. Departamento de Pediatria da Universidade Federal do Rio Grande do Norte (Natal,. Brasil); 3. Pós-graduanda do Programa de Pós-graduação em Ciências da Saúde da. Universidade Federal do Rio Grande do Norte (Natal, Brasil); 4. Departamento de Medicina Clínica da Universidade Federal do Rio Grande do. Norte (Natal, Brasil).. Correspondente: José Brandão-Neto. Av. Gal. Gustavo Cordeiro de Farias, s/n, Natal-RN, CEP 59012-570, Brazil. Tel +55 84 3342 9748 Fax +55 84 3342 9776 [email protected].

(19) 17. ABSTRACT. Introduction: The elderly generally show decreased muscle performance, accompanied by low consumption of dietary zinc. It is reported that zinc has positive effects on muscle performance. The aim of this study was to evaluate the influence of zinc on strength, muscular endurance, and balance in older women. Methodology: A randomized double-blind placebo-controlled clinical trial with 38 participants randomly subdivided into 4 groups: a control group comprised of 18 young women aged between 20 and 30 years, thus subdivided: Young Placebo (n = 9) ingested a placebo (sorbitol 10%), Young zinc (n = 9) ingested 25 mg of zinc. An experimental group of 20 elderly women, aged between 60 and 80 years and subdivided as: Elderly Placebo: (n = 10) ingested a placebo; Elderly Zinc (n = 10) ingested 25 mg of zinc. The follow-up lasted 90 days. The strength, endurance, and muscular balance (hamstring/quadriceps) were estimated by isokinetic peak torque, normalized by body weight, of the quadriceps, and hamstrings in the angular velocities of 60°/s (force), and 180°/s (resistance). Results: Compared with the strength of the Young placebo hamstring group, the Elderly Zinc showed a proportional increase in strength, and the Elderly Placebo group was significantly reduced. The same was seen for hamstrings resistance, only that the Elderly Placebo group showed a significant reduction compared to the Young Placebo group. Effect within each group: a significant increase in strength and endurance of the hamstrings in the Elderly Zinc group, and a significant decrease in the Elderly Placebo group. Mean difference(Δ) between Elderly Zinc and Elderly Placebo for hamstring strength was significant for (PT/kg IQS60°/s Δ = 8.97 Nm, p = 0.02) and for resistance (PT/kg IQS 180°/s Δ = 11.88 Nm p = 0.01). Conclusions: The study showed that zinc may be effective in increasing the strength and endurance of the hamstring, (a vulnerable muscle), and prevents disproportionate reduction of its strength relative to the quadriceps, atypical muscle imbalance that increases the risk of falls in older people. Keywords: Aging. Zinc, Nutrition, Muscle strength, Dynamometer, muscle strength..

(20) 18. Introduction Population aging is a reality on all continents1, and results in the need for the elderly to seek ways to address the related challenges; high prevalence of chronic disease, and functional disability2. All this may predispose this population to develop the Fragility Syndrome, compromising both their quality of life and interfering in their autonomy. Additional commitments and financial input from their families and the state are required to aid these people with their new needs in regard to personal care3. These factors are also directly or indirectly linked to demographic and socioeconomic factors, as well as to other aspects health2. During aging, muscle performance is directly associated with decreased functional capacity4. Sarcopenia, characterized by reduced number, size 5, and vascularization of the muscle fibers4, is directly related to accelerating muscle mass loss,after 60 years of age6, and has a direct effect on muscle strength reductions in the elderly 5. Reduced muscle mass and strength are associated with increased oxidative stress, which may be potentiated due to lower anaerobic and aerobic enzyme activity, and protein losses, and not just due to decreased physical activity 7. There is evidence that zinc deficiency in the body can affect striate8 muscle function, and can induce apoptosis of vascular smooth muscle cells. Oxidative stress combined with zinc deficiencies, would contribute to this cellular apoptosis9. Zinc is an abundant transition element in the brain, it plays an important role in the stabilization of basic myelin proteins, and the formation of the myelin sheath 10, it is involved in the development and preservation of peripheral nervefunctions 11, and in preserving the amount of muscle fibers, and their energy metabolism12. Zinc was also demonstrated to influence the total isokinetic work of the extensor muscles in the shoulders and knees in young men13. During prolonged restrictions of motor activity, it appears that endogenous mechanisms of zinc homeostasis are modified. Zorbas et al. 14 showed that rats kept in hypokinesia, did not guarantee tissue zinc penetration (normally deposited in bones and muscles) even when receiving dietary zinc supplements. Increased zinc in plasma, fecal and urinary excretions was also observed, resulting in significant losses of corporalzinc14..

(21) 19. In healthy aging, skeletal muscle shows a significant reduction in isokinetic muscle strength (especially in women), increased stiffness of the muscle fiber, reduced phosphorylation of the myosin light chains, and diminished actin and myosin cross-bridge kinetics, which results in low rates of force production15. There are also reductions in muscle cross-sectional area, type I fiber percentage, capillaritizedarea5 and a decline in mitochondrial oxidative capacity4. Older people with an active lifestyle show partial compensation, preserving mitochondrial oxidative capacity. An active lifestyle helps retain antioxidant capacity. In contrast, in the sedentary elderly, mitochondrial function is compromised with deregulation of the redox function. This anomaly may increase chronic inflammatory processes, which make the intracellular spaces of skeletal muscle an environment prone to toxicity, as mediated by reactive oxygen species (ROS)16. Proper zinc nutrition is essential to preserve muscle function8. Its deficiency, a characteristic of human aging, results in decreased immune response, and development of chronic degenerative diseases. 17. , which may predispose the elderly. to long periods of restricted movement, and make them vulnerable to precipitate fecal and urinary excretion of zinc, thus decreasing corporalzinc14. Decreased muscle strength related to age, called dynapenia by Clark and Maniniin 200818, has significant consequences for the aged, and increases the risks of functional limitations, disabilities and mortality. 19. . Study shows that dynapenia of. the quadriceps and wrists are independent predictors of mortality20. Thus, we see the clinical relevance of dynapenia studies. During human aging there is usually a gradual change from an active to sedentary lifestyle. The sedentary lifestyle is associated with chronic inflammatory disease, sarcopenia16, and dynapenia20. Zinc, being recognized as an anti– inflammatory21, could prevent the evolution of dynapenia, since the hand grip strength is negatively associated with levels of urinary 8-hydroxy-20-deoxyguanosine (8-OHdG)22. Based on the above, the present study aims to investigate the effectiveness of zinc supplementation (25 mg Zn++/day) in preventing strength, endurance, and quadricep/hamstring muscle balance losses in young and elderly women..

(22) 20. Materials and methods. Patient and study design. The volunteers, 60 to 80 years old were selected from a population of healthy elders3, as routed by the doctors of three family health clinics in the 3rd Sanitary District of the city of João Pessoa (PB), and by active search of the medical records of families enrolled at these health clinics. After selection, a home visit (with the agent responsible for the covered area of the local Family Health Clinic) was made in order to inform the volunteers about the research, and to invite their participation. The study included women; who practiced physical activities twice a week (at most), were residents in the areas covered by the study, which agreed to participate freely, and were aged from 20 to 30, and from 60 to 80. Women with a history of diseases such as diabetes mellitus, liver disease, thyroid disease, neurological disease, and rheumatoid arthritis were excluded. Besides these were excluded; users of medications that interfere with nerve function, and/or of pharmacological vitamin and mineral supplements, or which had a history of recent surgery. Those who were under hormone replacement therapy, or with mental illness, or had been bedridden during the last two months for more than two weeks, or whom did not agree to participate in the study were also excluded. Initially, we pre-selected 56 women between 60 and 80 years of age. After initial assessments, 20 women were excluded: two for not being able to leave home during the evaluations, four were living in another neighborhood with their children, eleven were self-medicating with anti-inflammatory, analgesic, and/or vitamin supplements, three walked every day and practiced gym exercise three times a week. Thirty-six women were referred for specialist clinical assessment in rheumatology, endocrinology, gastroenterology, cardiology, and neurology. At this stage, four with knee osteoarthritis, one with gastritis, two with diabetes, three with carbohydrate intolerance, and two with hypothyroidism were excluded. After these assessments, 24 elderly participants were selected and were the basis for selecting the pairs of young women to form the control group. The young women aged between 20 and 30 years were selected from the same area covered by.

(23) 21. the family health clinics of the older women, following all the procedures for evaluating the elderly.. Ethics. After being informed about all stages of the research, the reading and signing of the informed consent (as approved by the Ethics and Research Committee, Center of Health Sciences, Federal University of Paraiba (Protocol. 0193) was completed. Who agreed to be a volunteer then signed.. Experimental Design. Clinical randomized double blind controlled placebo. The professional responsible for carrying and storing bottles containing the zinc supplement and placebos was also responsible for group randomization, drawn randomly 1:1, randomly distributed into 4 groups. The control group included 18 young women between 20 and 30 years of age, and was subdivided into: Young Placebo: (n = 9) ingesting (10% sorbitol); Young Zinc: (n = 9) ingesting 25mg of elemental zinc/day. The experimental group comprised 20 elderly women aged between 60 and 80 years old, and was subdivided into: Elderly Placebo: (n = 10)ingesting a placebo(10% sorbitol); Elderly Zinc:(n = 10) ingesting 25 mg of zinc/day. The women were supplemented with 25 mg of zinc daily in the form of heptahydrated zinc sulfate (ZnSO47H2O, Merck, Darmstadt, Germany). The solutions of zinc, and the placebo (10% sorbitol) were prepared at the Department of Pharmacotechnics (UFRN, Brazil). Each volunteer was given a bottle of white matte plastic, containing 30 ml. A drop contained 5 mg of the element Zn++, or placebo (10% sorbitol). The volunteers were instructed to add 5 drops of the solution to a piece of bread, juice, or milk daily for breakfast. The study lasted for seven months. Each week 10 women were randomly selected to begin the experimental phase that lasted 90 days. The women drawn were referred by the professional responsible for randomization. Assessments started for the first phase of the study. After the final procedure of the assessment, they would receive a bottle containing a solution of.

(24) 22. either zinc or placebo that they would use during the ninety days. In the end all of the assessment procedures were performed for the initial stage.. Instruments and data collection procedures. Anthropometric assessment. The weights and heights of the participants were obtained on a manual balance (Elmer) with a capacity of 150 kg, 100 g precision, and a metal scale of 200 cm with a precision of 1 cm, leveled and calibrated (Balmak; BK50F, Sao Paulo, SP, Brazil). The body mass index (BMI) was obtained from the ratio weight/height 2.. Evaluation of alimentary consumption. The food intake assessment was performed using an estimated weekly food intake based on three days, two days mid-week, and one day on the weekend. The volunteers were instructed to properly perform the technique of food accounting, noting the time of each meal, and all food consumed in their respective home measures. The calculation of energy, macronutrients, fiber, calcium, iron, and zinc consumed (from the menus) was done through the Nut Win software version 1.5 a Nutrition Support Program, provided by the Department of Health Informatics, Federal University of São Paulo/UNIFESP. We also used the Brazilian Food Composition Table (TACO), provided by the Center for Studies and Research in Food (NEPA), State University of Campinas (UNICAMP)23.. Assessment of physical activity. The level of physical activity was measured using the Baecke physical activity questionnaire (modified for elders), and used to characterize a homogeneous physical activity group 24..

(25) 23. Evaluation of strength, endurance, and muscle balance. Peak isokinetic torque, normalized by body weight(PT/kg) to assess strength, endurance, and muscle balance,. 25. was measured at angular velocities of 60°/s, and. 180°/s,on a Computerized Isokinetic Dynamometer (Biodex Multi-Joint System 3,Biodex System Biomedical Inc, New York, USA),at the Laboratory for Analysis of Muscular Performance, Department of Physical Therapy, UFRN. The dynamometer was calibrated before each session, as described in the equipment manual. All tests were performed by the same physician in all phases of the study. Women performing the tests initiated a brief warm-up for five minutes on a stationary bicycle, adjusted to a resistance of 25 W at a speed of 20 km/h. They then conducted quadriceps stretching for both limbs. The stretching was conducted with the volunteers standing erect, the knee in complete flexion, and the hip extended to the maximum tolerable amplitude. Each maneuver was maintained for 30 seconds and repeated three times, at an interval of 30 seconds. After stretching, each participant was positioned on the dynamometer chair with the backrest reclined (with respect to the vertical position) by 5°. The participant’s trunk (thorax) is stabilized by means of two cross straps, and a transverse strap fixes the waist (pelvis). The support of the dynamometer lever arm was positioned in the distal region of the leg, 5 cm above the lateral malleolus, so that a complete arc of ankle dorsiflexionis allowed. The mechanical axis of rotation of the dynamometer was aligned with the lateral epicondyle of the femur (the axis of rotation of the knee joint). During all testing procedures, all women were told to hold firmly to the lateral seat support so as to keep all body segments stabilized. Adjustments to correct the effect of gravity on the torque were performed with the knee at 60°, and calculated by the dynamometer software. After a brief period of familiarization with the dynamometer, three sub maximal contractions were performed. The volunteers were then instructed to relax completely for three minutes. After this interval, they began is kinetic evaluation in the non-dominant limb. The isokinetic dynamometer was set in isokinetic mode, with the angular velocities at 60°/s and 180º/s. Five repetitions with the angular velocity at 60°/s(rated power), and fifteen repetitions with the angular velocity at 180°/s (rated resistance), and the hamstrings/quadriceps ratio was used to assess relative muscularbalance25. The.

(26) 24. three-minute rest period was maintained between sets to minimize the effects of fatigue.. Collection of biological material. 8 mL of blood were collected: 2 mL for zincexamination (BD Vacutainer, Trace Element, Serum, BD Franklin Lakes, NJ,USA), 2 mL for hematologic tests (VacuetteK3EK3EDTA, Greiner Bio -One, Monroe, North Carolina, USA), 2 mL for biochemical tests, and 2 mL for hormonal dosage (Z Vacuetteserumclotactivator, GreinerBio-One, Monroe, North Carolina, USA).The samples for zinc were immediately kept at a temperature of 37oC in a stainless steel oven, suitable for metals. Six hours later, the tubes were taken, and the sera collected with plastic ferrules, and stored in plastic tubes with metal-free caps. Hemolyzed samples were discarded because red blood cells are richer in zinc than is plasma. All procedures related to the handling of zinc samples were followed according to international standards. The serum samples were stored in a freezer at -20ºC until analysis.. Laboratory analyzes. Hormones (GH, IGF - 1, IGFBP3, E2, LH, FSH, TSH, T4) were measured by chemiluminescence (Immulite 1000 systems), the blood count was performed by an auto-analyzer(Horiba ABX Diagnostics, Micros 60, Montpellier, France), glucose, total protein, albumin, alanine transaminase, aspartate transaminase, total bilirubin, urea, creatinine and lipids were analyzed by auto analyzer (DadeBehring, Dimension AR, Illinois, USA). Zinc was determined by atomic absorption spectrophotometry (AA - 240FS, Varian, Victoria, Australia) according to the manufacturer's instructions.. Statistical Analysis. Data normality was assessed by the Shapiro-Wilk test. The data of the descriptive statistics were presented in a table as the mean, standard deviation, and mean difference (Δ). To detect the homogeneity between the groups, the parametric test one- way ANOVA was used with post hoc Tukey. The difference in average peak.

(27) 25. torque, normalized by body mass (PT/kg) for the quadriceps and hamstring muscles, at the angular velocities of 60°/s and 180°/s, and the muscle equilibrium ratio (between hamstrings/quadriceps) were analyzed. We compared between the control group Young Placebo, and the experimental Elderly Placebo and Elderly Zinc groups(one-way ANOVA) at the beginning and at the end of testing. The difference of effects within each group was made by paired the Student's t test. The treatment effect, comparing the Zinc Elderly with the Placebo Elderly group was made from the difference between the averages of the initial and the final evaluations, by independent t test.. RESULTS. The final sample consisted of 20 elderly women and 18 young women. In table 1 are summarized the characteristics of homogeneity between the groups. After analyzing the data, the randomization layout of the groups was revealed. To compare the effectiveness of zinc on force (PT/kg 60°/s), on resistance (PT/kg180°/s), and on muscle balance (IQS/QUA) in aging, the control group of reference was the Young Placebo group, which was not affected by zinc supplementation. In Table 2, the differences in averages (Δ), and standard deviations between the control group Young Placebo with the experimental groups Elderly Zinc and Elderly Placebo are expressed. In the initial measures of muscle strength APT/kg IQS 60°/s, the percentage difference between the groups Young Placebo and Elderly Zinc was 9.24%, between Young Placebo and Elderly Placebo it was 18.33%, no significant differences. Following 90 days of supplementation with 25 mg, the Elderly Zinc group had peak torque increased PT/kg IQS 60°/s by 8:18 Nm, with no significant difference in muscle strength continuing in the Young Placebo group. However, the Elderly Placebo group in contrast observed a decrease in PT/kg IQS 60°/s of 1.50 Nm from their initial measurements(A) representing a significant 30,45% reduction in strength when compared to the Young Placebo group. In the original measurement APT/kg QUA 60°/s, there was a significant percentage of difference in strength between the Young Placebo and Elderly Zinc groups of 28.24%,between the Young Placebo and Elderly Placebo groups, the difference was 29%. In the follow-up DPT/kg QUA 60°/s measurements we observed.

(28) 26. reductions in strength difference between the Young Placebo, and Elderly Zinc groups at 22.83%, between the Young Placebo and Elderly Placebo groups it was 24%, the difference was not significant. As to muscle balance between the hamstrings and quadriceps (AIQS/QUA 60°/s), it was observed that the Young Placebo group showed lower muscular balance than the two elderly groups, which could expose their knees to damage. The evaluation, after 90 days of supplementation with 25 mg zinc revealed that the Elderly Zinc group maintained muscle balance within limits, but were 7.74% above the Placebo Young control group. However, in the Elderly Placebo group, there was a decreased muscle balance (DIQS/QUA 60°/s Nm) of 18.69% compared to the Young Placebo group. Concerning. hamstring. muscle. strength,. in. the. initial. (APT/kg. IQS. 180°/s),measurements a significant difference between the Young Placebo group and the Elderly Zinc group of 31.76%, and between the Young Placebo and Elderly Placebo group of26.86%, was observed, which shows decreasing hamstring strength with age. In the follow-up measurements, after 90 days of supplementation with zinc, increased hamstring resistance in the Elderly Zinc group was observed. The increase was enough to verify no significant differences between the Elderly Zinc and the Young placebo groups. However, in the Elderly Placebo group we observed decreased hamstring muscle strength, and a greater significant difference between the Young Placebo and the Elderly Placebo groups. When the effect of zinc supplementation was compared in the same group between the initial measurement sand after 90 days, as seen in Table 3,the Elderly Zinc group showed significant increases (10.93%) in the strength of the hamstrings (PT/kg ISQ 60°/s), and significant increases (10.22%) in the quadriceps muscle (PT/kg QUA 60°/s). This represented an increase of 1.28%in the strength balance between the hamstrings and the quadriceps (ISQ/QUA 60°/s), approximating 60%. However, in the Elderly Placebo group seen in Table 4, there was a decrease of 2.56% in the strength of the hamstrings (PT/kg ISQ 60°/s), and significant increase of 9.80% in quadriceps strength (PT/kg QUA 60°/s), which represented a significant decrease of 12.78% in the balance of muscle strength (ISQ/QUA 60°/s). Muscular endurance analyzed before and after 90 days in the Elderly Zinc group showed a significant increase of 16.46%for the hamstring (PT/kg ISQ 180°/s), and the mean increase was 9.21% for the quadriceps (PT/kg QUA 180°/s). This.

(29) 27. represented an increase of 10.39% in the muscle strength balance (ISQ /QUA 180°/s). In contrast, it was found that for the Elderly Placebo group (in comparing the initial assessments with the subsequent 90 days of experiment), there was a decrease of 6.79% in the hamstring strength(PT/kg ISQ 180°/s), and 5.65% increase in quadriceps strength, this represented a decrease of 15.28% in the muscle strength balance (ISQ/QUA 180°/s). The effect of zinc supplementation between the Elderly Zinc group, and the Elderly Placebo, seen in Table 5, shows a significant increase in both strength and endurance for the hamstring muscles and the quadriceps. It can be assumed that zinc supplementation of 25 mg may be effective in the prevention of muscle strength and endurance losses, while increasing muscle strength and endurance in healthy women over 60 years of age.. DISCUSSION. The main results of this study show that supplementation of 25 mg daily for a period of 90 days increased strength, endurance, and muscle balance in women between 60 and 80 years of age. This may contribute to the prevention of strength, endurance, and muscular balance losses common during aging. It was found that daily zinc intake was below recommended levels in all three groups, both for age and for sex 26. However, serum zinc levels were within the reference standard normal27. In this nutritional condition, and in the initial assessment of hamstring strength measured by peak torque normalized by body weight at an angular velocity of 60°/s, the Young Placebo control had 9.24% more power than the Elderly Zinc group and 18.33% more than the Elderly Placebo group. No significant differences. However, the follow-up measurement showed that the Young placebo group had increased hamstrings strength (12.66%), and in the Elderly Zinc group, increased strength was 10.81%.In contrast the Elderly Placebo group showed reduced strength (2.56%). This decreased hamstring strength generated a significant difference of 30.45% compared to the Young Placebo group. Serum zinc observed in follow-up was seen ata significant reduction of 22.50% in the Young placebo group; the Elderly Placebo group saw a significant reduction of 9.8%. However in the group supplemented with 25 mg of zinc (Zinc Elderly), serum zinc reduction was.

(30) 28. insignificant. This shows that in the Young Placebo group, who increased their hamstring strengths by 12.66 that zinc may have been used in intramuscular structures thus reducing its availability in the plasma by 22.50%, leaving the group at the upper limit of zinc deficiency27. In the Elderly Placebo group, a significant reduction in serum zinc represented a reduction of force of 2.56%. This shows the importance of adequate amounts of zinc in the diet to preserve the strength of the hamstrings, since the supplemented Elderly Zinc group at 25 mg of zinc for ninety days, seems to have used the additional zinc, and secured increases in strength. This muscle group is extremely important in muscular balance for older people25. Zinc could also reduce or prevent hamstring injuries characteristic of aging. 28. .It is. reported that to preserve muscle function, zinc is essential for proper nutrition8. Its deficiency is characteristic of human aging, and leads to immune response decreases, and the development of chronic degenerativediseases 17. Of interest in this study was the quadriceps strength. In the initial evaluation, strength of the quadriceps for the Young Placebo group was 28.24% higher than the Elderly Zinc group and larger by 29%than the Elderly Placebo group, significant differences. In the follow-up measure, the difference in strength between the groups decreased as the Elderly Zinc group increased by 10.22%, the group Elderly Placebo by 9.8%, and the Young Placebo group by only 3.46%. The proportionate gains of force, both in the hamstring muscles as well as the quadriceps for the Elderly Zinc group resulted in a better muscular balance. In contrast, in the Elderly Placebo group, decreased strength of the hamstrings to 1.50 Nm, and increased strength in the quadriceps of 12.53 Nm, led to a significant decrease in muscular balance from 51.59 ± 7.74 to 45.74 ± 8.24. Accordingly, with muscle imbalance, an overload of the quadriceps can occur, because the most requested of movements, from sitting to standing position, spares the hip extensor. 29. .. During normal walking, balance between the flexor and extensor musculature is necessary for perfect dynamism between the concentric and eccentric contractile mechanisms. Because of aging, lesions of the quadriceps and hamstring muscle groups can interfere with this mechanism, due to decreased potential for muscle tissue regeneration mortality. 30. . Elderly people with lower muscle strength have higher rates of. 31. . Muscular force reduction18is closely related to decreased muscle mass. with age5. Reductions in strength, and muscular endurance, as well as unbalanced.

(31) 29. knee flexor and extensor muscles are inversely correlated with pain, stiffness, and functionality25. A Brazilian study of the elderly with mean ages of 69 ± 3.64 years, established benchmarks for balance between the knee flexors and extensors (the hamstrings, and quadriceps)at an angular velocity of 60°/s: 47.95 ± 10.99% and an angular velocity of 180°/s: 59.59 ± 13, 40% 32.In our study the approximate age of the women was by groups Elderly Zinc: 66.40 ± 6.20, and Elderly Placebo: 65.30 ± 5.03.Our study showed that at the angular velocity of 60°/s the muscular balance between flexors and extensors (during the initial evaluation of Elderly Placebo group) was 51.59 ± 7.74%, close to the reference values above. In the follow-up measurements, the balance between flexors and knee extensors of 45.74 ± 8.24% was lower, both in terms of their initial measurements as with the elderly of reference. 32. . However, in the. Elderly Zinc group,(initial average of 58.09 ± 11.29% and final average of 58.84 ± 9.90), the average hamstring/quadriceps balance, the equilibrium force directed to the knee joint, was maintained at 22.27%,above the average benchmark for this parameter. 32. . These results indicate what zinc supplementation can do in addition to. other factors that improve the health of the elderly. 26, 27. , and it may also be effective. in increasing muscular strength, especially the hamstring muscles. In the muscle balance measurements (ISQ/QUA180°/s), the Elderly Placebo group showed an initial mean of 61.69 ± 11.95, and a final average of 53.51 ± 6.21, the Elderly Zinc group showed an initial mean of 57, 98 ± 11.29, and final average of 64.70 ± 9.79. Therefore, the present study showed that the average strength of the muscle balance of the knee joint 90 days after the first assessment of Elderly Placebo group was 11.25% lower than the reference population. In contrast, the Elderly Zinc group after the same time was 7.9% higher than the reference population average. 32. . The increase in muscle balance in strength and resistance. seen in this study could make it easier to change from the sitting position to the standing position, or the starting and maintaining walking speed for a longer time. With reference to the comparison between the muscle balance averages outlined in this study, and the reference population32, there is evidence that zinc supplementation might be beneficial to prevent muscle imbalance for both strength and endurance. This is because the final averages for the group of women which were supplemented with zinc during 90 days at an angular velocity of 60°/s,.

(32) 30. maintained close to 60%, and at the angular velocity of 180°/s they were close to 65%. This might help to focus future studies elucidating the role of zinc in muscle strength and endurance. During aging, the hamstrings are most vulnerable to injury because a one-year increase in age increases the likelihood of tendon injury in this muscle group 1.3 times. 33. . Actions that develop increased muscle strength can be effective in. improving the daily life of elderly women, and contribute to the maintenance and extension of their autonomy, of the functional capabilities of this population 34, 35. The hamstrings are a muscle group, with a predominance of fast twitch type II muscle fibers. In healthy aging, there is a reduction of skeletal muscle fiber type I, of capillaritzed area4, of strength, and of cross-sectional area. In the hamstrings, the femoral biceps are made up of mainly 2c fibers that can become fast fiber or slow, depending on the demand for action requested. 36. .. Reduction of muscle mass and muscle strength is associated with increased oxidative stress and may be increased due to lowered activity of anaerobic and aerobic enzymes, and protein content, not just due to decreased physicalactivity7. There is evidence that zinc deficiency in the body can adversely affect the function of striated muscle 8,and can induce apoptosis of vascular smooth muscle cells; oxidative stress with zinc deficiency could contribute to the apoptosis of these cells 9. Acute depletion of zinc in the body; also changes the working capacity of skeletal muscle. 13. . However, the effectiveness of zinc in the metabolism depends on. lifestyle, because in experimental conditions of restricted mobility in mice, zinc supplementation was not effective in maintaining its metabolic balance 14. To preserve muscle function, proper zinc nutrition is essential. 8. because zinc. deficiency in human aging causes a decrease in the immune response, and the development of chronic degenerativediseases 17. The significant difference between the initial and follow-up averages for both strength and endurance of the hamstrings between the Elderly Zinc and Elderly Placebo groups shows the vulnerability of this muscle during aging. The decrease in strength, endurance, and balance was minimized with zinc supplementation, while increasing strength,. muscular endurance,. and balance in the older zinc. supplemented women was observed. This indicates that adequate zinc nutrition can prevent loss of strength and muscle endurance in women over 60 years. Accordingly,.

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(37) 35. Table 1. Bioanthropometrics and health characteristics between Young Placebo, Elderly Zinc, and Elderly Placebo Groups Young Placebo (n=9). ElderlyZinc (n=10). ElderlyPlacebo(n=10). Age. 24.11±2.97. 66.40±6.20*. 65.30±5.03*. Monthly income. 1732.40±1080. 1544.60±1111. 2210.30±1865. Body mass(kg). 62.45±15.44. 62.45±15.44. 64.26±10.67. Height(m). 1.61±0.04. 1.50±0.08*. 1.51±0.03*. BMI(kg/m²). 23.75±5.41. 25.96±5.33. 27.82±4.03. Physical Activity. 4.94±3.19. 6.98±2.57. 6.56±2.83. RBC(million/mm3). 4.45±0.19. 4.48±0.35. 4.56±0.30. Diet zinc(mg/dia). 7.42±1.15. 5.74±2.17. 6.54±2.09. Zinc (μg/mL). 1.081±0.06. 1.068±0.11. 1.079±0.04. Note- * Statistical significance (p ≤ 0.05). BMI= Body Mass Index; RBC= Red Blood Cell.

(38) 36. Table 2. Peak torque; normalized by body mass of the quadriceps and hamstrings in the angular velocities of 60°/s and 180°/s, for Young Placebo, Elderly Placebo and Elderly Zinc Groups (one-way ANOVA). Elderly. Young. Elderly. Placebo (n=9). Zinc (n=10). APT/kg IQS-60°/s,Nm. 73.50±25.59. 66.71±13.13. 0.73. 6.79. DPT/kg IQS-60°/s,Nm. 84.15±27.60. 74.89±14.46. 0.57. APT/kg QUA- 60°/s,Nm. 162.44±43.69. 116.58±24.64. DPT/kg QUA 60°/s,Nm. 168.25±59.75. APTIQS/QUA 60°/s,Nm. p. Δ2. 60.03±18.56. 0.30. 13.47. 9.26. 58.53±16.37. 0.02. 25.62*. 0.01. 45.86*. 115.34±29.24. 0.013. 47.10*. 129.84±29.61. 0.11. 38.41. 127.87±30.04. 0.13. 40.38. 45.00±8.97. 58.09±11.23. 0.01. -13.09*. 51.59±7.74. 0.29. -6.59. DIQS/QUA 60°/s,Nm. 54.29±18.23. 58.84±9.90. 0.71. -4.54. 45.74±8.09. 0.31. 8.55. APT/kg IQS 180°/s,Nm. 65.75±18.10. 44.87±15.49. 0.01. 20.88**. 48.09±8.63. 0.03. 17.66**. DPT/kg IQS 180°/s,Nm. 68.06±21.74. 53.71±9.18. 0.10. 14.35. 45.03±11.34. 0.006. 23.03**. APT/kg QUA 180°/s,Nm. 117.73±32.83. 77.26±24.07. 0.01. 40.47**. 79.33±15.55. 0.006. 38.40**. DPt/kg QUA 180°/s,Nm. 125.42±41.46. 85.09±19.88. 0.01. 40.33. 84.06±18.54. 0.009. 41.36*. A IQS/QUA 180°/sNm. 56.73±8.90. 57.98±11.87. 0.96. -1.24. 61.69±11.95. 0.59. -4.95. DIQS/QUA 180°/s,Nm. 57.56±18.29. 64.70±9.79. 0.42. -7.13. 53.51±6.21. 0.75. 4.05. A Zinc (μg/mL). 1.0816±0.06039. 1.0683±0.1167. 0.93. 0.0132. 1.0796±0.0472. 0.99. 0.0020. D Zinc (μg/mL). 0.8383±0.0865. 1.006±0.1387. 0.005. -0.1679. 0.9738±.0736. 0.02. -0.1354. P. Δ1. Placebo (n=10). Note - * Statistical significance (p ≤ 0.05). Δ1= (difference of means between Young placebo and Elderly Zinc); Δ2= (difference of means between Young Placebo and Elderly Placebo. A = measured before supplementation, D = measurements after the 90 days of supplementation with zinc, PT = peak torque, Nm = Newton.meter; kg = body mass; QUA= quadriceps; ISQ = hamstring ISQ /QUA = hamstrings and quadriceps ratio.

(39) 37. Table 3. Peak torque (normalized by body mass) of the quadriceps and hamstrings at angular velocities of 60°/s and 180°/s of the Elderly Zinc group (t test stopped). Elderly Zinc 95% confidence interval. PT/kg IQS 60°/s Nm. PT/kg QUA 60°/s Nm. Before. After. P. Δ. 66.71±13.13. 74.89±14.46. 0.02. -8.18*. 116.58±24.64. 129.84±29.61. 0.01. 58.09±11.23. 58.84±9.90. 0.85. -0.74. PT/kg IQS 180°/s Nm. 44.87±15.49. 53.71±9.18. 0.01. -8.84*. 77.26±24.07. 85.09±19.88. 0.01. Upper. Limit. Limit. -14.99. -1.36. -23.12. -3.39. -9.39. 7.90. -15.60. -2.07. -13.57. -2.08. -14.22. 0.78. -0.0256. 0.1505. -13.26*. IQS/QUA 60°/s Nm. PT/kg QUA 180°/s Nm. Lower. -7.83*. IQS/QUA 180°/s Nm. 57.98±11.87. 64.70±9.79. 0.07. -6.72. Zinc (μg/mL). 1.068±0.1167. 1.0059±0.1471. 0.14. 0.0624. Note - * Statistical significance (p ≤ 0.05). PT = peak torque, Nm = Newton meter; kg = body mass; ISQ = hamstrings, QUA = quadriceps, and ISQ/QUA = hamstrings to quadriceps ratio: Δ = difference between averages before and after.

(40) 38. Table 4. Peak torque normalized by body mass of the quadriceps and hamstrings in the angular velocities of 60°/s and 180°/s Elderly Pacebo group (t test stopped).. ElderlyPlacebo Confidenceinterval95% Before. PT/kg IQS 60°/s Nm. After. (n = 10). (n = 10). Mean ± SD. Mean ± SD. 60.03±18.56. 58.53±16.37. p. Δ. 0.61. 1.50. PT/kg QUA 60°/s Nm. 115.34±29.24. 127.87±33.04. 0.02. -12.53*. IQS/QUA 60°/s Nm. 51.59±7.74. 45.74±8.24. 0.001. 5.84*. PT/kg IQS 180°/s Nm. 48.09±8.63. 45.03±9.18. 0.32. 0.06. PT/kg QUA180°/s Nm. 79.33±15.55. 84.06±18.54. 0.15. -4.73. IQS/QUA 180°/s Nm. 61.69±11.95. 53.51±6.02. 0.07. 8.18. Zinc (μg/mL). 1.0796±0.0472. 0.9593±.0612. 0.001. 0.1202. LowerLimit. UpperLimit. -4.91. 7.91. -22.60. -2.45. 3.09. 8.59. -3.54. 9.66. -11.54. 2.08. -1.03. 17.39. 0.0692. 0.1712. Note - * Statistical significance (p ≤ 0.05). PT = peak torque, Nm = Newton meter; kg = body mass; ISQ = hamstrings,QUA = quadriceps, and ISQ/QUA = hamstrings to quadriceps ratio; Δ = difference between the averages before and after.

(41) 39. Table 5. Difference of averages before and after 90 days (independent t test) of peak torque/body mass of the quadriceps and hamstrings, angular velocities of 60°/s and 180°/s, between Elderly Zinc and ElderlyPlacebogroups Elderly. Elderly Placebo. Confidence Interval. Zinc(n=10). (n=10). Mean ± SD. Mean ± SD. Δ. P. Lowest. Highest. PT/kg IQS 60°/s Nm. 8.29±9.44. -1.50±8.97. 9.97*. 0.02. 1.13. 18.44. PT/kgQUA 60°/s Nm. 15.95±19.29. 11.82±15.65. 4.13. 0.60. -12.30. 20.56. PT/kg IQS 180°/s Nm. 8.82±9.45. -3.06±9.15. 11.88*. 0.01. 3.13. PT/kg QUA 180°/s Nm. 7.83±8.03. 4.73±9.53. 3.10. 0.44. -5.18. Note - * Statistical significance (p ≤ 0.05). PT = peak torque, Nm = Newton.meter; kg = body mass ; QUA = quadriceps, ISQ = hamstrings, Δ = average difference between. 20.62. 11.38.

(42) 40. 6 ANEXAÇÃO DO ARTIGO 2. ARTIGO 2. Título: Influence of basal energy expenditure and body composition on bone mineral density in postmenopausal women Periódico: International Journal of General Medicine ISSN: 1178-7074 (Electronic) Qualis: B2 (Medicina II – QUALIS CAPES) Status: Publicado.

(43) 41. International Journal of General Medicine. Dovepress open access to scientific and medical research. Original Research. Open Access Full Text Article. Influence of basal energy expenditure and body composition on bone mineral density in postmenopausal women This article was published in the following Dove Press journal: International Journal of General Medicine 2 November 2012 Number of times this article has been viewed. Maria Aparecida Bezerra Quirino1 João Modesto-Filho2 Sancha Helena de Lima Vale3 Camila Xavier Alves3 Lúcia Dantas Leite4 José BrandãoNeto5. Background: The aim of this study was to investigate the influence of body mass index,. 1Department. spine, femoral neck, Ward’s triangle, and trochanteric bone mineral density. In regard to time since menopause, we also observed significant negative correlations with bone mineral density at. of Physiotherapy, 2Department of Clinical Medicine, Universidade Federal da Paraíba, João Pessoa, Brazil; 3Postgraduate Health Science Program, 4Department of Nutrition, 5Department of Clinical Medicine, Universidade Federal do Rio Grande do Norte, Natal, Brazil. body weight, lean mass, fat mass, and basal energy expenditure on bone mineral density in postmenopausal women. Methods: This was a cross-sectional, descriptive study of a sample of 50 women, with minimum time since menopause between 1 and 10 years. Bone mineral density was assessed at the lumbar spine (L2–L4), femoral neck, Ward’s triangle, and trochanter using dual-energy X-ray absorptiometry. Body mass index, lean mass, fat mass, and basal energy expenditure were measured by bioimpedance. Results: The mean age of the women was 51.49  3.86 years and time since menopause was 3.50  2.59 years. Significant negative correlations were found between chronological age and lumbar. the lumbar spine and Ward’s triangle. The following significant positive correlations were recorded: body mass index with bone mineral density at the femoral neck and trochanter; fat mass with bone mineral density at the femoral neck and trochanter; lean mass with bone mineral density at the lumbar spine, femoral neck, and trochanter; and basal energy expenditure with bone mineral density at all sites assessed. On the other hand, the multiple linear regression model showed that: 20.2% of bone mineral density variability at the lumbar spine is related to lean mass and time since menopause; 22.3% of bone mineral density variability at the femoral neck is related to body weight and age; 18.9% of bone mineral density variability at Ward’s triangle is related to age and basal energy expenditure; and 39% of bone mineral density vari-ability at the trochanter is related to body mass index, age, and menarche. Conclusion: Changes in bone mineral density, specific for each skeletal site, are influenced. by age, time since menopause, body weight, body mass index, lean mass, and basal energy expen-diture. Lean mass and basal energy expenditure positively influenced bone mineral density at the lumbar spine and Ward’s triangle, with a predominance of trabecular bone. Keywords: women, menopause, bone mineral density, body composition, energy expenditure. Introduction Correspondence: José BrandãoNeto Av Gal Gustavo Cordeiro de Farias, s/n, Natal-RN, CEP 59012570, Brazil Tel 55 84 3342 9748 Fax 55 84 3342 9776 Email [email protected]. Demographic changes predicted for the next 50 years indicate that the number of elderly people will increase worldwide, together with metabolism-related diseases.1 Among these, osteoporosis in postmenopausal women is recognized as an important public health problem because it is associated with a high risk of fracture, elevated morbidity and mortality rates, and incurs high financial and societal costs.2.